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 Q]: Problem: a store reported total sales of $ 460 million for february of this year. if the total sales for the same month last year was $ 320 million, approximately what was the percent increase in sales ?
Options: a. 2 %, b. 17 %, c. 44 %, d. 65 %, e. 83 %
[EX A]: c

[EX Q]: Problem: a rhombus has area 432 sq m, one diagonal is 36 cm. find other diagonal ?
Options: ['a. 2400 m', 'b. 2500 m', 'c. 2600 m', 'd. 2700 m', 'e. 2900 m']
[EX A]: a

[EX Q]: Problem: if a person walks at 20 km / hr instead of 10 km / hr, he would have walked 20 km more. the actual distance traveled by him is :
Options: a. 20 km, b. 56 km, c. 60 km, d. 70 km, e. 80 km
[EX A]:
a