Answer: A . John Glenn was able to complete his mission safely.
Step-by-step explanation:
Katherine Johnson was a brilliant mathematician that helped immensely in the project to get the United States into space. She was so good with math that she was labelled the ''human computer'' and earned the trust of several people at NASA including astronaut, John Glenn.
John Glenn did not trust the machine projections for his mission and so called in Katherine to double check the calculations made by the computer. After she had confirmed the results, he felt confident enough to fly and so was able to complete his mission safely.