Name three roles or jobs that are the most important in our world and explain why?

Engineering, scientists, medical

I'm pretty sure it's c. extremely gradual but not 100% sure though.

Historians are researchers of the past or people who understand the history of people. with this field, they must possess qualities such as being unbiased, patient, efficient reader, has a knack for logic and critical thinking and reasoning, disciplined, open-minded, resourceful, with good analytical ability, good reasoning skills and problem solving!