Question: Who is the child of the president that was informed of an assassination by George Christian?

full_context: Document 1: List of presidents of the United States by age: The oldest living U.S. president is George H.W. Bush, born June 12, 1924 (age 93 years, 261 days). On November 25, 2017, he also became the longest - lived president, surpassing the lifespan of Gerald Ford, who died at the age of 93 years, 165 days. The second oldest living president, Jimmy Carter, has the distinction of having the longest post-presidency in U.S. history, currently at 37 years, 39 days. He surpassed the previous record, held by Herbert Hoover (31 years, 230 days) on September 7, 2012. The youngest living president is Barack Obama, born August 4, 1961 (age 56 years, 208 days).
Document 2: United States Secret Service: In 1968, as a result of Robert F. Kennedy's assassination, Congress authorized protection of major presidential and vice presidential candidates and nominees. In 1965 and 1968, Congress also authorized lifetime protection of the spouses of deceased presidents unless they remarry and of the children of former presidents until age 16.
Document 3: Assassination of Robert F. Kennedy: In November 2006, the BBC's Newsnight program presented research by filmmaker Shane O'Sullivan alleging that several CIA officers were present on the night of the assassination. Three men who appear in films and photographs from the night of the assassination were positively identified by former colleagues and associates as former senior CIA officers who had worked together in 1963 at JMWAVE, the CIA's main anti-Castro station based in Miami. They were JMWAVE Chief of Operations David Morales, Chief of Maritime Operations Gordon Campbell and Chief of Psychological Warfare Operations George Joannides. However, several people who had known Morales, including family members, were adamant that he was not the man who O'Sullivan said was Morales. After O'Sullivan published his book, assassination researchers Jefferson Morley and David Talbot also discovered that Campbell had died of a heart attack in 1962, six years prior to the assassination of Kennedy. In response, O'Sullivan stated that the man on the video may have used Campbell's name as an alias. He then took his identifications to the Los Angeles Police Department whose files showed the men he identified as Campbell and Joannides to be Michael Roman and Frank Owens, two Bulova sales managers attending the company's convention in the Ambassador. O'Sullivan stood by his allegations stating that the Bulova watch company was a "well-known CIA cover".
Document 4: List of presidents of the United States by age: The oldest living U.S. president is George H.W. Bush, born June 12, 1924 (age 93 years, 346 days). On November 25, 2017, he also became the longest - lived president, surpassing the lifespan of Gerald Ford, who died at the age of 93 years, 165 days. The second oldest living president, Jimmy Carter, has the distinction of having the longest post-presidency in U.S. history, currently at 37 years, 124 days. He surpassed the previous record, held by Herbert Hoover (31 years, 230 days) on September 7, 2012. The youngest living president is Barack Obama, born August 4, 1961 (age 56 years, 293 days).
Document 5: Elizabeth Cutter Morrow: Elizabeth Cutter Morrow, born Elizabeth Reeve Cutter (May 29, 1873 – January 24, 1955) was an American poet in the early 20th century, and she became the first female head of Smith College, acting as college president from 1939 to 1940, but she was never officially granted the title. She was the wife of U.S. Senator Dwight Morrow and the mother of four children, which included Anne Morrow Lindbergh, distinguished American author and wife of aviation pioneer Charles Lindbergh.
Document 6: Lynda Bird Johnson Robb: Lynda Bird Johnson Robb (born March 19, 1944) is an American chairwoman who served as chairwoman of the Board of Reading is Fundamental, the nation's largest children's literacy organization, as well as chairwoman of the President's Advisory Committee for Women. She is also a magazine editor who served as First Lady of Virginia from 1982 to 1986, before that as Second Lady of Virginia from 1978 to 1982. She is the elder of the two daughters of former United States President Lyndon Baines Johnson and former First Lady Lady Bird Johnson. She is the oldest living child of a U.S. President following the death of John Eisenhower on December 21, 2013.
Document 7: Loriene Roy: Loriene Roy is an American librarian from Texas. She was the first Native American president of the American Library Association when she was inaugurated in 2007.
Document 8: List of presidents of the United States by age: The median age upon accession to the presidency is 55 years and 3 months. This is how old Lyndon B. Johnson was at the time of his inauguration. The youngest person to assume the office was Theodore Roosevelt, who became president at the age of 42 years, 322 days, following William McKinley's assassination; the oldest was Donald Trump, who was 70 years, 220 days old at his inauguration. The youngest person to be elected president was John F. Kennedy, at 43 years, 163 days of age on election day; the oldest was Ronald Reagan, who was 73 years, 274 days old at the time of his election to a second term.
Document 9: Silent Vigil at Duke University: Immediately following the assassination of Martin Luther King, Jr., the Silent Vigil (also shortened to the Vigil) was a social protest at Duke University that not only demanded collective bargaining rights for AFSCME Local 77, the labor union for nonacademic employees, but also advocated against racial discrimination on campus and in the surrounding community of Durham, North Carolina. Occurring from April 4, 1968, to April 12, 1968, members of the University Christian Movement began planning a campus-wide vigil in memoriam of Dr. King. Another group of undergraduate students called for a protest march to address prevalent issues concerning the primarily African-American nonacademic employees at Duke in Local 77. Together, both student groups, along with the support of Local 77, most of the teaching faculty, and civilians not affiliated with the university, sparked a non-violent demonstration that involved over 2,000 participants, making it the largest in Duke's history.
Document 10: Assassination of Martin Luther King Jr.: President Lyndon B. Johnson was in the Oval Office that evening, planning a meeting in Hawaii with Vietnam War military commanders. After press secretary George Christian informed him at 8:20 p.m. of the assassination, he canceled the trip to focus on the nation. He assigned Attorney General Ramsey Clark to investigate the assassination in Memphis. He made a personal call to King's wife, Coretta Scott King, and declared April 7 a national day of mourning, on which the U.S. flag would be flown at half-staff.
Document 11: Mary Harrison McKee: Mary Scott Harrison McKee (April 3, 1858 – October 28, 1930) was the only daughter of President Benjamin Harrison and his wife Caroline Scott Harrison. After her mother died in 1892, McKee served as her father's "de facto" First Lady for the remainder of his term.
Document 12: Civil rights movement: SNCC had undertaken an ambitious voter registration program in Selma, Alabama, in 1963, but by 1965 little headway had been made in the face of opposition from Selma's sheriff, Jim Clark. After local residents asked the SCLC for assistance, King came to Selma to lead several marches, at which he was arrested along with 250 other demonstrators. The marchers continued to meet violent resistance from police. Jimmie Lee Jackson, a resident of nearby Marion, was killed by police at a later march in February 17, 1965. Jackson's death prompted James Bevel, director of the Selma Movement, to initiate and organize a plan to march from Selma to Montgomery, the state capital.
Document 13: Lyndon B. Johnson: Lyndon Baines Johnson (/ ˈlɪndən ˈbeɪnz /; August 27, 1908 -- January 22, 1973), often referred to by his initials LBJ, was an American politician who served as the 36th President of the United States from 1963 to 1969, assuming the office after having served as the 37th Vice President of the United States from 1961 to 1963. A Democrat from Texas, he also served as a United States Representative and as the Majority Leader in the United States Senate. Johnson is one of only four people who have served in all four federal elected positions.
Document 14: Half-mast: For thirty days after the death of a current or former president or president - elect, as occurred after the death of President Reagan and the death of President Ford. For ten days after the death of a current vice president, current or retired chief justice, or current Speaker of the House of Representatives. From the day of death until interment of an Associate Justice of the Supreme Court, a secretary of an executive or military department, a former vice president, the President Pro Tempore of the Senate, or the governor of a state, territory, or possession. On the day of death and the day after for a Member of Congress. On Memorial Day until noon. Every September 11 in remembrance of the September 11 attacks. Upon presidential proclamation, usually after the death of other notable figures or tragic events.
Document 15: Lord & Taylor: Starting in June 2000, Jane Elfers served as Lord & Taylor's second female president. She was replaced in October 2008 by former Neiman Marcus executive, Brendan Hoffman. According to HBC executive chairman, Richard Baker, her contract had expired. A third female president, Bonnie Brooks, took over in 2011, and a fourth female president, Liz Rodbell, took over in 2013.
ground_truth: Lynda Bird Johnson Robb
sub_queries: Whom did George inform of an assassination? Answer: Lyndon B. Johnson
Lyndon B. Johnson >> child Answer: Lynda Bird Johnson Robb