The Charges for Renting a Moving Van Are $\$ 65$ For the First 40 Miles And

The charges for renting a moving van are $\$ 65$ for the first 40 miles and $\$ 7$ for each additional mile. Assume that a fraction of a mile is rounded up.
a. Determine the cost of driving the van 98 miles.
b. Find a symbolic representation for a function $\mathrm { f }$ that computes the cost of driving the van $x$ miles, where $0 < x \leq$ (Hint: express f as a piecewise-constant function.)

A) a. $\$ 6776$ ;
b. $f ( x ) = \left\{ \begin{array} { l l } 65 & \text { if } 0 < x \leq 40 \\ 65 x + 7 ( x - 40 ) & \text { if } 40 < x \leq 100 \end{array} \right.$
B) a. $\$ 471 ;$
b. $f ( x ) = \left\{ \begin{array} { l l } 65 & \text { if } 0 < x \leq 40 \\ 65 + 7 ( x - 40 ) & \text { if } 40 < x \leq 100 \end{array} \right.$
C) a. $\$ 471 ;$
b. $f ( x ) = \left\{ \begin{array} { l l } 65 & \text { if } 0 < x \leq 40 \\ 65 + 7 ( x + 40 ) & \text { if } 40 < x \leq 100 \end{array} \right.$
D) a. $\$ 1031$ ;
b. $f ( x ) = \left\{ \begin{array} { l l } 65 & \text { if } 0 < x \leq 40 \\ 65 + 7 ( x + 40 ) & \text { if } 40 < x \leq 100 \end{array} \right.$