Does money have to be involved when you talk about opportunity cost? Why or why not?

Opportunity cost is the profit lost when one alternative is selected over another. ... Opportunity cost does not necessarily involve money. It can also refer to alternative uses of time. For example, do you spend 20 hours learning a new skill, or 20 hours reading a book?

i dont know. sorry : (

the answer is a) to be able to obey them.