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: two taps a and b can fill a cistern in 12 minutes and 18 minutes respectively. they are turned on at the same time. if the tap a is turned off after 4 minutes, how long will tap b take to fill the rest of the cistern ?
Options: a. 8 min., b. 9 min., c. 10 min., d. 7 min., e. none of these
a

Problem: | - 2 | ( | - 25 | - | 5 | ) = ? ? source: preparation material mba center
Options: a. 40, b. – 60, c. 60, d. 75, e. 100
a

Problem: how many positive integers less than 5,000 are evenly divisible by neither 14 nor 21 ?
Options: a. 4,514, b. 4,475, c. 4,521, d. 4,428, e. 4,349

e