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: a person ' s present age is two - fifth of the age of his mother. after 8 years, he will be one - half of the age of his mother. how old is the mother at present
Options: a. 38, b. 40, c. 42, d. 44, e. 45

Ex Output:
b


Ex Input:
Problem: if ( x - 10 ) ( y - 5 ) ( z - 2 ) = 1000 then what is the least value of x + y + z ? if x, y, z are all integer no.
Options: a. 7, b. 8, c. 9, d. 10, e. 11

Ex Output:
a


Ex Input:
Problem: allay ' s internet provider offers unlimited traffic which costs $ 0.5 per day charged off at 12 a. m. the service is discontinued when client ' s debt exceeds $ 5. if today in the morning allay makes a payment of $ 7, for how many days, including today, will she be connected to the internet without any additional payments, given her initial balance was $ 0 ?
Options: a. 15, b. 24, c. 25, d. 26, e. 13

Ex Output:

c