What is the definition of work according to the text?

I. Work is a human activity aimed at producing goods and services to meet needs.
II. Work is a physical and mental effort that requires effort.
III. Work is an activity that does not dignify man.
IV. Work is a free activity with no economic purpose.
a) I and II are correct.
b) II and IV are correct.
c) I and III are correct.
d) III and IV are correct.