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: what is the value of n if the sum of the consecutive odd intergers y from 1 to n equals 169 ?
Options: a. 47, b. 25, c. 37, d. 33, e. 29

A: b
****
Q: Problem: a certain sum is invested at simple interest at 18 % p. a. for two years instead of investing at 12 % p. a. for the same time period. therefore the interest received is more by rs. 300. find the sum ?
Options: a. 7000, b. 2500, c. 2778, d. 2800, e. 2791

A: b
****
Q: Problem: if henry were to add 8 gallons of water to a tank that is already 3 / 4 full of water, the tank would be 7 / 8 full. how many gallons of water would the tank hold if it were full ?
Options: a. 25, b. 40, c. 64, d. 80, e. 96

A:
c
****