I would choose B. exosphere. Astronomers study outer space, planets and ect.
A vector has a size and a direction. The size is called the magnitude of the vector.
Kylie Kristen Jenner (born August 10, 1997)[3] is an American media personality, socialite, model, and businesswoman. She has starred in the E! reality television series Keeping Up with the Kardashians since 2007 and is the founder and owner of cosmetic company Kylie Cosmetics.
