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 plant manager must assign 12 new workers to one of five shifts. she needs a first, second, and third shift, and two alternate shifts. each of the shifts will receive 3 new workers. how many different ways can she assign the new workers ?
Options: a. 2430, b. 2640, c. 3300, d. 4860, e. 5400
A:
b