Tim Is Thin, and He Wants to Gain Weight for Football

Tim is thin, and he wants to gain weight for football. He does not have an eating disorder. The best way for Tim to proceed would be to

A) eat only high-fat foods and lift weights.
B) combine a balanced, calorie-dense diet with strength training.
C) train twice a day and consume lots of high-calorie foods.
D) combine resistance training with an over-the-counter weight gaining supplement.