Definition: Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.
Input: Problem: machine a takes 50 hours to complete a certain job and starts that job at 6 am. after four hour of working alone, machine a is joined by machine b and together they complete the job at 1 pm. how long would it have taken machine b to complete the job if it had worked alone for the entire job ?
Options: a. 9, b. 88.88, c. 4.88, d. 2.88, e. 3.88
Output:
e