A.I. Explanation:

Option 1: "Even some routine activities can serve as light exercise."

Explanation: The text mentions that activities like brisk walking, climbing stairs, and gardening can be considered light exercise. This supports the idea that even routine activities can contribute to physical activity.

Option 2: "If putting your body into complete shape is your aim, you might be in for some disappointment."

Explanation: The text states that improvement in body shape will be minimal with light exercise, indicating that those seeking significant changes may be disappointed. This aligns with the statement about aiming for complete body shape.

Option 3: "It is necessary to exercise different parts of the body daily."

Explanation: The text does not mention the necessity of exercising different body parts daily. Instead, it emphasizes the benefits of regular light exercise without specifying the need for variety in muscle groups.

Option 4: "Put in some aerobic activity for working up a sweat."

Explanation: While the text discusses light exercise, it does not specifically advocate for aerobic activities aimed at sweating. It focuses more on the benefits of light, regular activities rather than intense aerobic workouts.

Option 5: "It builds resistance to chronic diseases and infections, and your heart performs strongly."

Explanation: Although the text mentions benefits like immunity to colds and flu and heart health, it does not explicitly state that light exercise builds resistance to chronic diseases. The phrasing in this option is too broad and not directly supported by the text.