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.

Example Input: Problem: after giving a discount of rs. 45 the shopkeeper gets a loss of 10 %, if the cost price is rs. 180. find the markup % ?
Options: a. 0.21, b. 0.2, c. 0.17, d. 0.21, e. 0.15
Example Output: e

Example Input: Problem: a train running at the speed of 20 km / hr crosses a post in 10 seconds. what is the length of the train ?
Options: a. 150, b. 250, c. 415, d. 200, e. 312
Example Output: d

Example Input: Problem: carmen made a sculpture from small pieces of wood. the sculpture is 2 feet 10 inches tall. carmen places her sculpture on a base that is 10 inches tall. how tall are the sculpture andbase together ?
Options: a. 3.1 feet, b. 3.66 feet, c. 3.3 feet, d. 3.4 feet, e. 3.5 feet
Example Output:
b