please help me this question answer:
In 2016, David Hay started his own business, Hays Gardening and Landscapes. David was previously an employer of another business/
a) What was the opportunity costs for David when he started his business?

A. Cost of marketing to attract customers.

B. Loss of earnings from employment

C. Payment of taxes on profits

D. Risk of business failure

ANSWER:

b) Explain why this answer is correct?

Opportunity cost refers to the loss of other alternatives when another alternative is being chosen. It is the potential benefit that an individual, firm or government misses out on when a different alternative is being selected.

Based on the question given, the opportunity costs for David when he started his business will be the earnings that he got from his previous employment such as the wages or the salaries, bonuses etc. Since he has began his own business, he can't enjoy those benefits anymore.