You will be given a definition of a task first, then some input of the task.
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: each of the products produced yesterday was checked by worker x or worker y. 0.5 % of the products checked by worker x are defective and 0.8 % of the products checked by worker y are defective. if the total defective rate of all the products checked by worker x and worker y is 0.55 %, what fraction of the products was checked by worker y ?
Options: a. 1 / 3, b. 1 / 4, c. 1 / 5, d. 1 / 6, e. 1 / 8
Output:
d