An air conditioning repair service call costs $75 per hour plus a flat fee trip change of $25. If the situation can be represented by the function r(h)=75h+25, what do the variables represent and which is the dependent variable

A. The repair time h depends on the repair changes r in hours
B. The repair changes h depends on the repair time r in hours
C. The repair changes r depends on the repair time h in hours
D. The repair time r depends on the repair time h in hours