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.

Ex Input:
Problem: for 2 consecutive yrs, my incomes are in the ratio of 4: 7 and expenses in the ratio of 3: 5. if my income in the 2 nd yr is rs. 42000 & my expenses in the first yr in rs. 23000, my total savings for the two - year is
Options: a. s. 8000, b. s. 9000, c. s. 9900, d. s. 9990, e. s. 10000

Ex Output:
a


Ex Input:
Problem: bill made a profit of 10 % by selling a product. if he had purchased that product for 10 % less and sold it at a profit of 30 %, he would have received $ 63 more. what was his original selling price ?
Options: a. $ 850, b. $ 990, c. $ 1050, d. $ 1180, e. $ 1340

Ex Output:
b


Ex Input:
Problem: crazy eddie has a key chain factory. eddie managed to decrease the cost of manufacturing his key chains while keeping the same selling price, and thus increased the profit from the sale of each key chain from 20 % of the selling price to 50 % of the selling price. if the manufacturing cost is now $ 50, what was it before the decrease ?
Options: a. $ 20, b. $ 40, c. $ 50, d. $ 80, e. $ 100

Ex Output:

d