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: a furniture dealer purchased a desk for $ 150 and then set the selling price equal to the purchase price plus a markup that was 40 % of the selling price. if the dealer sold the desk at the selling price, what was the amount of the dealer ' s gross profit from the purchase and the sale of the desk ?
Options: a. $ 40, b. $ 60, c. $ 80, d. $ 90, e. $ 100
[EX A]: e

[EX Q]: Problem: two guys a and b leave point a and point b simultaneously and travel towards point b and point a on the same route at their respective constant speeds. they meet along the route and immediately proceed to their respective destinations in 32 minutes and 50 minutes respectively. how long will b take to cover the entire journey between point b and point a ?
Options: a. 65, b. 90, c. 70, d. 75, e. 80
[EX A]: b

[EX Q]: Problem: if equation | x / 5 | + | y / 5 | = 2 encloses a certain region on the coordinate plane, what is the area of this region ?
Options: a. 20, b. 50, c. 200, d. 100, e. 400
[EX A]:
c