Simplify the Difference Quotient for the Linear Function $f(x)$ , and Use It to Identify the Rate of Change

Multiple Choice

Simplify the difference quotient for the linear function $f(x)$ , and use it to identify the rate of change of the function.
- $f(x) =7 x+2$

A) -7
B) 2
C) -2
D) 7