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: a 16 % stock yielding 10 % is quoted at :
Options: a. 83.33, b. 110, c. 112, d. 120, e. 160
e

Problem: for each of her sales, a saleswoman receives a commission equal to 20 percent of the first $ 500 of the total amount of the sale, plus 35 percent of the total amount in excess of $ 500. if the total amount of one of her sales was $ 800, the saleswoman ’ s commission was approximately what percent of the total amount of the sale ?
Options: a. 22 %, b. 24 %, c. 25 %, d. 26 %, e. 28 %
d

Problem: two trains of length 100 meters and 200 meters are 450 meters apart. they are moving towards each other on parallel tracks, at speeds of 90 km / h and 72 km / h. after how many seconds will the trains meet ?
Options: a. 6, b. 8, c. 10, d. 12, e. 14

c