The Monthly Cost of Driving a Car Depends on the Number

Multiple Choice

The monthly cost of driving a car depends on the number of miles driven. Julia found that in October it cost her $\$ 200$ to drive $300 \mathrm { mi }$ and in July it cost her $\$ 350$ to drive $600 \mathrm { mi }$ . Express the monthly $\operatorname { cost } C$ as a function of the distance driven $d$ assuming that a linear relationship gives a suitable model.
Select the correct answer.

A) $C = - 50 d + 0.5$
B) $C = 50 d - 0.5$
C) $C = 0.5 d + 50$
D) $C = 2 d + 50$
E) $C = 0.5 d - 50$