A company employee has to print 3145 copies of a 1-page document to be mailed to clients. The company's printer prints 85 pages per minute. The function f(x)=−85x+3145 represents the number of unprinted pages x minutes after the printing begins.

What is the practical domain of function f?

A all whole numbers from 0 to 37
B all multiples of 85 between 0 and 3145
C all real numbers from 0 to 37
D all real numbers from 0 to 3145