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: if s is the sum of reciprocals of a list of consecutive integers from 55 to 64, inclusive, s is approximately equal to
Options: a. 0.16, b. 0.2, c. 0.3, d. 0.4, e. 0.5
[EX A]: a

[EX Q]: Problem: anand finishes a work in 7 days, bittu finishes the same job in 8 days and chandu in 6 days. they take turns to finish the work. anand on the first day, bittu on the second and chandu on the third day and then anand again and so on. on which day will the work get over ?
Options: a. 3 rd, b. 6 th, c. 9 th, d. 7 th, e. 8 th
[EX A]: d

[EX Q]: Problem: a rectangular block 15 cm by 30 cm by 75 cm is cut into an exact number of equal cubes. find the least possible number of cubes ?
Options: ['a. 6', 'b. 40', 'c. 15', 'd. 10', 'e. 22']
[EX A]:
d