Luke called a repairman to fix the furnace at his cabin. The repairman charged $35 per hour plus a fee of $25 for the service call, as represented by the expression in the box. (THE EXPRESSION IN THE BOX IS "35x + 25")

In the expression, what is represented by the variable x?

A) the number of hours it took the repairman to fix the furnace.

B) the distance in miles from the repairman's shop to Luke's cabin.

C) the number of service calls made by the repairman to Luke's cabin.

D) the total amount in dollars that Luke paid to have the furnace repaired.

(I need the answer ASAP)