21. Sammy has 7 Sunny Sun pictures. She wants to get a Sunny Cup. How can she get one? (A) Use 6 Sunny Sun pictures and pay $100. (B) Use 6 Sunny Sun pictures and pay $200. (C) Spend $150 to get 3 more Sunny Sun pictures. (D) Spend $200 to get 4 more Sunny Sun pictures.