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.

[Q]: Problem: a man ' s speed with the current is 18 km / hr and the speed of the current is 2.5 km / hr. the man ' s speed against the current is ?
Options: a. 10, b. 18, c. 50, d. 30, e. 40
[A]: b


[Q]: Problem: if the sum of 5 consecutive even positive integers is a, then the sum of the next 5 even consecutive integers in terms of a is :
Options: a. a + 5, b. a + 10, c. a + 25, d. a + 50, e. 2 a + 5
[A]: d


[Q]: Problem: a train 800 m long can cross a pole in 10 sec and then find the speed of the train ?
Options: a. 280, b. 282, c. 284, d. 286, e. 288
[A]:
e