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: 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
a

Problem: points a, b, c, and d, in that order, lie on a line. if ab = 3 cm, ac = 4 cm, and bd = 8 cm, what is cd, in centimeters ?
Options: a. 7, b. 2, c. 3, d. 4, e. 5
a

Problem: amar takes as much time in running 18 meters as a car takes in covering 12 meters. what will be the distance covered by amar during the time the car covers 1.6 km ?
Options: a. 6200 m, b. 2400 m, c. 300 m, d. 4300 m, e. 1200 m

b