The cost is expressed by the function y = 18x + 8, where x is the number of km and y is the totalcost. Interpret the rate of change and base fare from the function.1. The rate of change is 18 dollars per km and base fare is 8 dollars.2. The rate of change is -18 dollars per km and base fare is 8 dollars.3. The rate of change is 8 dollars per km and base fare is