The function f(x) = 0.11x + 43 relates how much derek pays for phone service, f(x), to the number of minutes, x, used for international calls in a month. what is the value and meaning of f(320)? a. $78.20; this is the amount derek pays for 320 months of service $78.20; / b. this is the amount derek pays for 320 minutes of international calls $92.50; / c. this is the amount derek pays for 320 months of service $92.50; / d. this is the amount derek pays for 320 minutes of international calls