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.
--------
Question: 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

Answer: e


Question: Problem: what is the units digit of 26 ! + 50 ! + 4 ! + 4 ! ?
Options: a. 8, b. 6, c. 4, d. 2, e. 0

Answer: a


Question: Problem: what is 2 2 / 3 - 1 1 / 4 divided by 1 / 2 - 1 / 3 ?
Options: a. 17 / 36, b. 36 / 17, c. 17 / 6, d. 17 / 2, e. 51 / 4

Answer:
d