The spending limit on John's credit card is given by the function L(x) = 0.8x + 10,000, where x is his monthly income. The variable x represents __ in the inverse function. If John's spending limit is $60,000, his monthly income is __.
A) Monthly Income, $75,000
B) Credit Card Limit, $60,000
C) Spending Limit, $10,000
D) Interest Rate, 0.8
