Question: Jay Clark Buckey, Jr., is an American physician and astronaut who flew aboard one space shuttle mission (STS-90) as a Payload Specialist, Buckey withdrew from the race when which former Governor, from New Hampshire, entered the race? 
Context: Jay Clark Buckey, Jr. (born June 6, 1956, in New York City) is an American physician and astronaut who flew aboard one space shuttle mission (STS-90) as a Payload Specialist.  Buckey briefly ran for the Democratic nomination to challenge New Hampshire Senator John E. Sununu, a first term Republican, when he was up for re-election in 2008.  Buckey withdrew from the race when former Governor Jeanne Shaheen entered the race. Millie Elizabeth Hughes-Fulford (born December 21, 1945) is an American medical investigator, molecular biologist and former NASA astronaut who flew aboard a NASA Space Shuttle mission as a Payload Specialist. Sultan bin Salman bin Abdulaziz Al Saud (Arabic: ‎ ‎ ) (born 27 June 1956) is a former Royal Saudi Air Force pilot who flew aboard the American STS-51-G Space Shuttle mission as a payload specialist, and a member of the House of Saud.  He is thus the first member of a royal family to be an astronaut, and the first Arab and Muslim to fly in outer space. John-David Francis Bartoe (born November 17, 1944 in Abington, Pennsylvania) is an American astrophysicist.  He is the Research Manager for the International Space Station (ISS) at NASA's Johnson Space Center.  He provides oversight for the Program Manager concerning the research capability, research hardware, and research plans of the ISS.  As a civilian employee of the US Navy, he flew aboard Space Shuttle mission STS-51-F as a Payload Specialist. James Anthony "Jim" Pawelczyk (born September 20, 1960) is an American researcher of physiology and Kinesiology who flew aboard the NASA STS-90 Space Shuttle mission as a Payload Specialist. STS-51-G was the eighteenth flight of NASA's Space Shuttle program, and the fifth flight of Space Shuttle "Discovery".  The seven-day mission launched from Kennedy Space Center, Florida, on June 17, 1985, and landed at Edwards Air Force Base, California, on June 24.  Sultan Salman Al Saud of Saudi Arabia was on board as a payload specialist; Al Saud became the first Arab, the first Muslim, and the first member of a royal family to fly into space.  It was also the first Space Shuttle mission which flew without at least one astronaut from the pre-Shuttle era among its crew. Chief Warrant Officer 4 Thomas John Hennen (born August 17, 1952) is a United States Army warrant officer and NASA astronaut who flew aboard Space Shuttle mission STS-44 as a Payload Specialist. Eugene Huu-Chau "Gene" Trinh (Vietnamese: Trịnh Hữu Châu, born September 14, 1950) is a Vietnamese American biochemist who flew aboard NASA Space Shuttle mission STS-50 as a Payload Specialist, becoming the first Vietnamese American astronaut in space. Paul Desmond Scully-Power, AM, FRAeS (born May 28, 1944) is an Australian born, American oceanographer.  In 1984, while a civilian employee of the United States Naval Undersea Warfare Center, he flew aboard NASA Space Shuttle mission STS-41-G as a Payload Specialist.  He was the first Australian-born person to journey into space, and the first astronaut to launch with a beard. Cynthia Jeanne Shaheen (née Bowers; January 28, 1947) is the senior United States Senator from New Hampshire, since 2009.
Answer: Jeanne Shaheen