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: a couple spent $ 211.20 in total while dining out and paid this amount using a credit card. the $ 211.20 figure included a 20 percent tip which was paid on top of the price which already included a sales tax of 10 percent on top of the price of the food. what was the actual price of the food before tax and tip ?
Options: a. $ 120, b. $ 140, c. $ 150, d. $ 160, e. $ 180
[EX A]: d

[EX Q]: Problem: a / ( b / c. in the expression above, a, b, and c are different numbers and each is one of the numbers 2, 3, or 6. what is the largest possible value of the expression ?
Options: a. 2 / 18, b. 6 / 3, c. 30 / 2, d. 18 / 2, e. 6 / 18
[EX A]: d

[EX Q]: Problem: a jar of 180 marbles is divided equally among a group of marble - players today. if 2 people joined the group in the future, each person would receive 1 marble less. how many people are there in the group today ?
Options: a. 16, b. 18, c. 20, d. 22, e. 24
[EX A]:
b