Which of following statements about career management is true?

If your choices are the following:
A Economic factors and new technologies often lead people to change occupations. 

B Most people remain in the same position for their entire working lives. 

C It's very rare for people to move to a different company during their careers. 

D Changing occupations always means developing an entirely new set of job skills.

Then the answer is A Economic factors and new technologies often lead people to change occupations.