Task: Question Answering
Input (English): The total monthly cost c to send \(x\) text messages is given by the function \(C(x) = 0.05x - 2.5\) for all \(x \geq 51\). If Hannah received a bill for \$10.50 for sending text messages last month, how many text messages did she send?
(A)60 (B)125 (C)160 (D)225 (E)260
Output (English): E