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.

Example 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
Example Output: a

Example Input: Problem: set a contains all the even numbers between 2 and 50 inclusive. set b contains all the even numbers between 62 and 110 inclusive. what is the difference between the sum of elements of set b and the sum of the elements of set a ?
Options: a. 1500, b. 3100, c. 4400, d. 6200, e. 7400
Example Output: a

Example Input: Problem: eddy and freddy start simultaneously from city a and they travel to city b and city c respectively. eddy takes 3 hours and freddy takes 4 hours to complete the journey. if the distance between city a and city b is 510 kms and city a and city c is 300 kms. what is the ratio of their average speed of travel ? ( eddy: freddy )
Options: a. 8 / 3, b. 3 / 8, c. 8 / 5, d. 5 / 8, e. 34 / 15
Example Output:
e