Pavan is making monthly payments of $110 to pay a loan of $8140. The function  f(x)=−110x+8140f(x)=−110x+8140 represents the amount he owes after making x payments.
 What is the practical domain of function f?
 all real numbers from 0 to 8140
 all whole numbers from 0 to 74
 all multiples of 110 between 0 and 8140
 all real numbers from 0 to 74