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 julie rows 32 km upstream and 72 km down steam taking 4 hours each, then the speed of the stream
Options: a. 1.5 kmph, b. 0.5 kmph, c. 0.4 kmph, d. 1.6 kmph, e. 2.5 kmph
[EX A]: b

[EX Q]: Problem: a fort had provision of food for 150 men for 45 days. after 10 days, 25 men left the fort. find out the number of days for which the remaining food will last.
Options: a. 44, b. 42, c. 40, d. 38, e. 36
[EX A]: b

[EX Q]: Problem: if pintu is coded as 79523 in a certain code language, how would you code lumbo in the same language ?
Options: a. 13426, b. 14236, c. 13436, d. 33426, e. 15263
[EX A]:
d