Read the text below and answer the question. "Regular exercise is vital for maintaining good health. It helps to strengthen your heart, improve your mood, and boost your energy levels. Even a moderate amount of physical activity, such as a brisk walk for 30 minutes most days of the week, can make a significant difference. Furthermore, exercise can help reduce the risk of chronic diseases like diabetes and heart disease." What is the main idea of this text?
A) Walking is the best form of exercise.