The three major areas of professional careers are

In order to be a professional on demand, you need to have some general profile like:Knowledge: You must know, be an expert in your professional career.Experience: Being an experimented professional is as important as knowledge, some companies give more important to experience.Social skills: In order to achieve goals, you need to be able to have interpersonal and intrapersonal intelligence.

I’m pretty sure that the answer is b.