Which expression could be used to solve this problem? Bart practices piano every day. First he practices songs for 20 minutes. Then he practices scales for 15 minutes. How much time does Bart practice piano in 3 days? A. 3 × (20 – 15) B. 20 × (15 + 3) C. 3 × (20 + 15) D. 20 × (15 – 3)