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 a mixture is 1 ⁄ 7 alcohol by volume and 2 ⁄ 7 water by volume, what is the ratio of the volume of alcohol to the volume of water in this mixture ?
Options: a. 4 / 2, b. 3 / 2, c. 1 / 2, d. 5 / 2, e. 7 / 2
[EX A]: c

[EX Q]: Problem: find the cost of fencing around a circular field of diameter 32 m at the rate of rs. 2 a meter ?
Options: a. 201, b. 132, c. 772, d. 592, e. 261
[EX A]: a

[EX Q]: Problem: alfred buys an old scooter for $ 4700 and spends $ 600 on its repairs. if he sells the scooter for $ 5800, his gain percent is ?
Options: a. 5.45 %, b. 6.23 %, c. 7 %, d. 9.43 %, e. 10 %
[EX A]:
d