Answer the following question: A man went to see a doctor."Open your mouth,"the doctor said.Then the man opened his mouth and the doctor looked in quickly. "It's clear what's wrong with you.You need more exercise,"the doctor said. "But,doctor,"the man said,"I don't think..." "Don't tell me what you think,"the doctor said."I am the doctor,not you.I know what you need.I see hundreds of people like you.None of them get any exercise.They sit in offices all day and in front of the television in the evening.What you need is to walk quickly for at least 20 minutes a day." "Doctor,you don't understand,"the man said."I..." "I don't want to hear any excuses,"the doctor said."You must find time for exercise.If you don't,you will get fat and have health problems when you are older." "But I walk every day,"the man said. "Oh,yes,and I know what kind of walking that is.You walk a few feet to the train station from your house,a few more feet from the station to your office,and a few more feet from your office to a restaurant for lunch and back.That's not real walking.I'm talking about walking in the park for twenty minutes every day." "Will you listen to me,doctor?"the man shouted,getting angry with this doctor who thought he knew everything."I'm a postman,"the man went on,"and I walk for seven hours every day." . The doctor thought many people had health problems only because they _ . A) did not have enough exercise B) did not eat healthy food C) spent much time watching TV D) were working in offices
Answer:
A