A computer manufacturer built a new facility for assembling computers. There were construction and new equipment costs. The company paid for these costs and made combined profits of $10 million after 4 years, as shown in the graph: Which equation most closely represents the line depicted in the graph?

a. f(x) = −10x + 4
b. f of x equals fifteen halves times x minus 20
c. f(x) = 10x − 4
d. f of x equals two fifteenths times x minus 20