Musiclover please help.

The function f(x) = 3x + 5,000 represents the amount of money a cell phone screen is being sold for, where x is the number of screens being manufactured.

The function g(x) = 20x − 400 represents the cost of production, where x is the number of screens being manufactured.

What is (f − g)(200)? Explain.
$2,000 is the profit made from 200 cell phone screens.
$9,200 is the profit made from 200 cell phone screens.
$2,000 is the cost of manufacturing 200 cell phone screens.
$9,200 is the cost of manufacturing 200 cell phone screens.