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.
Q: Problem: a grocery store bought some mangoes at a rate of 5 for a dollar. they were separated into two stacks, one of which was sold at a rate of 3 for a dollar and the other at a rate of for a dollar. what was the ratio of the number of mangoes in the two stacks if the store broke even after having sold all of its mangoes ?
Options: a. 1: 4, b. 16: 9, c. 2: 3, d. 1: 2, e. 2: 5
A:
b