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.

Problem: the salary of a person was reduced by 14 %. by what percent should his reduced salary be raised so as to bring it at par with his original salary ?
Options: a. 10 %, b. 16.3 %, c. 13.7 %, d. 15.1 %, e. 12.3 %
b

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
d

Problem: a shipment of 230 smartphones contains 84 that are defective. if a customer buys two smartphones at random from the shipment, what is the approximate probability that both phones are defective ?
Options: a. 1 / 250, b. 1 / 84, c. 1 / 11, d. 9 / 68, e. 1 / 3
d