I think its letter d if I really don't know this stuff but I'm trying to help someone I just in elementary school
Is unusual word within a book
Answer:
Explanation: Katherine Johnson, née Katherine Coleman, also known as (1939–56) Katherine Goble, (born August 26, 1918, White Sulphur Springs, West Virginia, U.S.—died February 24, 2020, Newport News, Virginia), American mathematician who calculated and analyzed the flight paths of many spacecraft during her more than three decades with the U.S. space program. Her work helped send astronauts to the Moon.