Answer:
a) tipping is seen as a reward for a good service provided. It is also a way of passing labor costs directly to the customer, which increases the restaurants' profits.
b) generally, most restaurant charge a fixed fee for tips. Maybe in the past customers could decide the tip, but that is not true now for most places. Although, customers are better judges of the service that they receive. By the way, the 15% is the minimum tip, customers can choose to increase that amount.
c) if the restaurants did not require tips, their labor costs would increase significantly.
Explanation: