37. Which sentence best expresses the central point (main idea) of the passage? (A) Naps of an hour or so after the midday meal were once popular and are still in favor in Latin American and European countries. (B) Naps, generally short ones about eight hours after waking, energize people mentally and physically. (C) According to sleep researchers, the human body is programmed to become sleepy in the early afternoon. (D) There are two types of naps: short ones that energize body and brain and long ones that make up for great sleep loss.