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: after giving a discount of rs. 45 the shopkeeper gets a loss of 10 %, if the cost price is rs. 180. find the markup % ?
Options: a. 0.21, b. 0.2, c. 0.17, d. 0.21, e. 0.15
[EX A]: e

[EX Q]: Problem: if ( x - 10 ) ( y - 5 ) ( z - 2 ) = 1000 then what is the least value of x + y + z ? if x, y, z are all integer no.
Options: a. 7, b. 8, c. 9, d. 10, e. 11
[EX A]: a

[EX Q]: Problem: in right triangle abc, ac is the hypotenuse. if ac is 35 and ab + bc = 55, what is the area of the triangle abc ?
Options: a. 225, b. 450, c. 25 2, d. 200, e. 200 2
[EX A]:
b