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: what percent is 6 gm of 1 kg ?
Options: a. 1.5 %, b. 0.5 %, c. 0.6 %, d. 3.5 %, e. 4 %
[EX A]: c

[EX Q]: Problem: a man traveled from the village to the post - office at the rate of 25 kmph and walked back at the rate of 4 kmph. if the whole journey took 5 hours 48 minutes, find the distance of the post - office from the village ?
Options: a. 70 m, b. 80 km, c. 20 km, d. 10 km, e. 73 km
[EX A]: c

[EX Q]: Problem: the price of 10 chairs is equal to that of 4 tables. the price of 15 chairs and 2 tables together is rs. 4000. the total price of 12 chairs and 3 tables is ?
Options: a. rs. 3900, b. rs. 4900, c. rs. 4980, d. rs. 5000, e. rs. 5900
[EX A]:
a