Answer: 5
Explanation: C
Consumer surplus is the difference between the quantity that a consumer is eager to pay for any product and the amount that he or she really ends up paying for that commodity. In this question Melanie was expecting to pay $79.95 when she saw the tag. Later she came to know that the coat was on a sale and she would have to pay 20% less. She finally paid $63.96 that is $15.99 less than the stated price $15.99. Thus, $15.99 is the consumers' surplus.