3. The writer says that people who only use cash a. tend to visit the bank more often. b. do not spend money that they do not have. c. are rich when they become older.

The reading mentions: "Another advantage to using cash is that a person cannot spend money that is not available. This stops a person from spending more than what he or she has." This directly supports option b.

Ответ: b. do not spend money that they do not have.