Q: 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.
Problem: a ' s speed is 20 / 13 times that of b. if a and b run a race, what part of the length of the race should a give b as a head start, so that b beats a by 80 % of the length of the race ?
Options: a. 44 %, b. 48 %, c. 52 %, d. 42 %, e. 87 %
A:
e