A woman becomes pregnant. Which of the following is the best thing she could do for her baby?

A. Take vitamin supplements and avoid doing any exercises that could harm the embryo.

B. Eat a balanced diet and avoid taking in anything that could harm the embryo.

C. Eat a diet high in protein and avoid anything containing fat or carbohydrates.

D. Gain at least 60 pounds and avoid any particularly strenuous exercise.