Vance sells between 300 and 310 items at a convention. He pays a one time $450 fee, and earns $15 commission for each item that he sells. The function p(i)=15i−450

represents Vance's convention earnings as a function of items sold.

What is the practical domain of the function?

A. all real numbers
B. 300≤i≤310
C. [300, 310]
D. all integers between 300 and 310 inclusive