Many people leave their servers tips in restaurants, even when they are not likely to visit the restaurant again. This is evidence that

A) people would rather pay for good service at an inexpensive restaurant than pay higher prices and receive poor service at an expensive restaurant.
B) people enjoy eating at restaurants more than eating at home.
C) people treat others fairly even if doing so makes them worse off financially.
D) there has been an improvement in the service people receive in restaurants over time, partly because the restaurant industry has become more competitive.

Answer: C