【单选题】People need exercise to stay healthy. Adults should exercise 20 minutes daily, but most people do not. Activities like swimming, lifting weights, and playing sports are often inconvenient or too expen...
A.
The best exercise is walking because it is easy, convenient, and usually done outside.
B.
Adults should exercise 20 minutes daily, but most people do not. Activities like swimming, lifting weights, and playing sports are often inconvenient or too expensive.