Question: What is the  2015 estimated wealth of Franklin Clarence Mars, founder of Mars, Incorporated?

Context paragraphs:
S. P. Hinduja: Srichand Parmanand Hinduja (born 28 November 1935) is an Indian-born British billionaire business magnate, investor, and philanthropist.  He is the primary shareholder and chairman of Hinduja Group of companies.  As of May 2017, together with his brother Gopichand he is the UK's richest man.  Since the 1990s, he has been consistently ranked among the UK and Asia's wealthiest people.  In May 2017, Hinduja topped the "Sunday Times" Rich List with an estimated wealth of GBP 16.2 billion ($21 billion).  Based on the rich list compiled by Asian Media & Marketing Group, Hinduja's wealth is estimated at GBP 19 billion ($24.7 billion).  The "Forbes" List in March 2016 ranked him and his brother GP as the world's 58th richest billionaire family with an estimated wealth of $16.4 billion.

Ethel V. Mars: Ethel Veronica Mars (1884 – December 25, 1945) was an American businesswoman and racehorse owner.  She was Ethel Veronica Healy prior to her marriage in 1910 to Franklin Clarence Mars, the founder of the Mars Candy company.

Mars to Stay: Mars to stay missions propose astronauts sent to Mars for the first time should intend to stay.  Unused emergency return vehicles would be recycled into settlement construction as soon as the habitability of Mars becomes evident to the initial pioneers.  Mars to Stay missions are advocated both to reduce cost and to ensure permanent settlement of Mars.  Among many notable Mars to Stay advocates, former Apollo astronaut Buzz Aldrin has been particularly outspoken, suggesting in numerous forums "Forget the Moon, Let’s Head to Mars!"  and, in June 2013, Aldrin promoted a manned mission "to homestead Mars and become a two-planet species."  In August 2015, Aldrin, in association with the Florida Institute of Technology, presented a "master plan", for NASA consideration, for astronauts, with a "tour of duty of ten years", to colonize Mars before the year 2040.  The Mars Underground, Mars Homestead Foundation, Mars One, and Mars Artists Community advocacy groups and business organizations have also adopted Mars to Stay policy initiatives.

Gopichand Hinduja: Gopichand Parmanand Hinduja (born 29 February 1940) is an Indian-born British billionaire businessman, the co-chairman of the Hinduja Group.  As of May 2017, together with his brother Srichand he is the UK's richest man.  Since the 1990s, he has been consistently ranked among the UK and Asia's wealthiest people.  In May 2017, Hinduja topped the "Sunday Times" Rich List with an estimated wealth of GBP 16.2 billion ($21 billion).  Based on the rich list compiled by Asian Media & Marketing Group, Hinduja's wealth is estimated at GBP 19 billion ($24.7 billion).  The "Forbes" List in March 2016 ranked him and his brother GP as the world's 58th richest billionaire family with an estimated wealth of $16.4 billion.

Malik Riaz: Malik Riaz Hussain (Urdu, Punjabi: ; born February 8, 1954) is a Pakistani businessperson, billionaire and philanthropist.  He is the founder and chairman of Bahria Town, the largest privately held real estate development company in Asia.  Riaz is currently the 7th richest person in Pakistan, with an estimated wealth of over a billion US$, he is one of Pakistan's most prominent philanthropists.

Forrest Mars Sr.: Forrest Edward Mars Sr. (March 21, 1904 – July 1, 1999) was an American businessman and the driving force of the Mars candy empire.  He is best known for introducing Milky Way (1923) and Mars (1932) chocolate candy bars, and M&M's (1941) chocolate candy, as well as orchestrating the launch of Uncle Ben's Rice.  He was the son of candy company Mars, Inc. founder Frank C. Mars and his first wife Ethel G. Mars (née Kissack).

Mars Nederland: Mars Nederland (English: Mars Netherlands ) is the Dutch division of Mars, Incorporated, a privately held multi-national company in food, pet care products, and confectionery products.  It has its headquarters and main production site in Veghel, North Brabant.  A second production site is located in Oud-Beijerland, South Holland.  The chocolate factory in Veghel is the largest production site owned by Mars, Incorporated, and is among the largest chocolate factories in the world.

Forrest Mars Jr.: Forrest Edward Mars Jr. (August 16, 1931 – July 26, 2016) was an American heir.  He was the eldest son of Audrey Ruth (Meyer) and Forrest Mars Sr., and the grandson of Frank C. Mars, the founder of Mars, Incorporated, the confectionery company.  In March 2015, "Forbes" estimated his wealth to be $26.8 billion

Franklin Clarence Mars: Franklin Clarence Mars ( ; September 24, 1882 – April 8, 1934), sometimes known as Frank C. Mars, was an American business magnate who founded the food company Mars, Incorporated, which mostly makes chocolate candy.  Mars' son Forrest Edward Mars developed M&M's and the Mars bar.

Jacqueline Mars: Jacqueline Mars (born October 10, 1939) is an American heiress and investor.  She is the daughter of Audrey Ruth (Meyer) and Forrest Mars, Sr., and granddaughter of Frank C. Mars, founders of the American candy company Mars, Incorporated.  In 2014, "Forbes" described Mars as the 20th richest American.

Supporting paragraphs: Forrest Mars Jr. Franklin Clarence Mars
Answer: $26.8 billion