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: the dimensions of a room are 10 m x 7 m x 5 m. there are 2 doors and 3 windows in the room. the dimensions of the doors are 1 m x 3 m. one window is of size 2 m x 1.5 m and the other 2 windows are of size 1 m x 1.5 m. the cost of painting the walls at rs. 3 per sq m is
Options: a. 2488, b. 378, c. 739, d. 474, e. 291
d

Problem: the l. c. m of two numbers is 495 and their h. c. f is 5. if the sum of the numbers is 100, then their difference is
Options: a. 19, b. 10, c. 28, d. 27, e. 29
b

Problem: if 1 / ( x + 4 ) + 1 / ( x - 4 ) = 1 / ( x - 4 ), what is the value of x ?
Options: a. 5, b. 4, c. 1, d. 2, e. 3

b