A salesperson makes a base salary of $2000 per month. Once he reaches $40,000 in total sales, he earns an additional 5% commission on the amount in sales over $40,000.

A. Write a piecewise-defined function to model the salesperson's total monthly salary S(x) (in $) as a function of the amount in sales x.

B. Graph the function.

C. Suppose the salesperson sold $95,000 worth of merchandise, what was his salary for that month?

D. Suppose the salesperson's total salary for a month was $4,800, what was his total sales for that month?

E. Find S(25000) and interpret what is means in the context of the problem.