After graduating college, Johnson…

A.
had a variety of career options to choose from.

B.
discovered that there were very few research mathematician positions open.

C.
taught school before eventually becoming a computer for the NACA.

D.
began training to become the first female astronaut.

It is not mentioned in the given statement whether Johnson had any specific career options or became the first female astronaut after graduating college. The answer choices provided are unrelated to the given information.