Detailed Instructions: 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: at joel ' s bookstore, the current inventory is 30 % historical fiction. of the historical fiction books, 40 % are new releases, while 50 % of the other books are new releases. what fraction of all new releases are the historical fiction new releases ?
Options: a. 4 / 25, b. 12 / 47, c. 2 / 5, d. 8 / 15, e. 2 / 3
A:
b