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 a randomly selected positive single digit multiple of 3 is multiplied by a randomly selected prime number less than 20, what is the probability w that this product will be a multiple of 45 ?
Options: a. 1 / 32, b. 1 / 28, c. 1 / 24, d. 1 / 16, e. 1 / 14
[EX A]: c

[EX Q]: Problem: find the curved surface area, if the radius of a cone is 35 m and slant height is 30 m ?
Options: a. 1100, b. 2200, c. 3300, d. 4400, e. 5500
[EX A]: c

[EX Q]: Problem: if the perimeter of a rectangular garden is 1800 m, its length when its breadth is 400 m is ?
Options: a. 500, b. 600, c. 700, d. 800, e. 900
[EX A]:
a