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: how much is 60 % of 40 is greater than 4 / 5 of 30 ?
Options: a. 8, b. 3, c. 7, d. 0, e. 1
[A]: d


[Q]: Problem: in one hour, a boat goes 19 km / hr along the stream and 9 km / hr against the stream. the speed of the boat in still water ( in km / hr ) is :
Options: a. 12 kmph, b. 13 kmph, c. 14 kmph, d. 15 kmph, e. 16 kmph
[A]: c


[Q]: Problem: a high school has 400 students 1 / 2 attend the airthmetic club, 5 / 8 attend the physics club and 3 / 4 attend the chemistry club. 3 / 8 attend all 3 clubs. if every student attends at least one club how many students attend exactly 2 clubs.
Options: a. 80, b. 70, c. 60, d. 50, e. 30
[A]:
d