Lea buys 20 picture frames. Some are 4 in. by 6 in. frames which cost $5.80 each, and the rest are 5 in. by 7 in. frames that cost$9.60 each. She spends a total of \$80.80. Which equation models this situation? Let f represent the number of 4 in. by 6 in. frames she buys. A. 9.6f + 5.8(20) = 80.8 B. 5.8f + 9.6(20 – f) = 80.8 C. (5.8 + 9.6)(20 – f) = 80.8 D. 9.6f + 5.8(f + 20) = 80.8