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: if price of t. v set is reduced by 20 %, then its sale increases by 80 %, find net effect on sale value
Options: a. 44, b. 45, c. 46, d. 47, e. 48
[EX A]: a

[EX Q]: Problem: a merchant marks his goods up by 30 % and then offers a discount of 10 % on the marked price. what % profit does the merchant make after the discount ?
Options: a. 17 %, b. 25 %, c. 69 %, d. 31 %, e. 19 %
[EX A]: a

[EX Q]: Problem: of the families in city x in 1994, 35 percent owned a personal computer. the number of families in city x owning a computer in 1998 was 20 percent greater than it was in 1994, and the total number of families in city x was 4 percent greater in 1998 than it was in 1994. what percent of the families in city x owned a personal computer in 1998 ?
Options: a. 50.12 %, b. 40.52 %, c. 40.56 %, d. 40.38 %, e. 40.14 %
[EX A]:
d