A sunk cost is A. a past cost that cannot be recovered. B. the cost for drilling certain types of wells, such as a well for water. C. a cost that is highly relevant for decisionminusmaking. D. an opportunity cost.

The correct answer is letter "A": a past cost that cannot be recovered.

Explanation:

Sunk costs are incurred in the past, irrespective of future events, and can not be recovered. Economists teach that sunk costs should not be taken into account when making a financial decision. Instead, the decision-makers should consider only future costs.

answer; (b) insider trading;

there is no following so id just amuse false