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 garden center sells a certain grass seed in 5 - pound bags at $ 13.80 per bag, 10 - pound bags at $ 20.43 per bag, and 25 - pound bags $ 32.25 per bag. if a customer is to buy at least 65 pounds of the grass seed, but no more than 80 pounds, what is the least possible cost of the grass seed that the customer will buy ?
Options: a. $ 98.73, b. $ 96.75, c. $ 98.78, d. $ 102.07, e. $ 105.3
a