I think it might be C. but I am unsure please help if you can!

Question

A company has two electric motors that consume varying amounts of power. The power consumed by each motor is a function of the time (t in minutes) for which it runs. The cost of power (in $) to run one motor is given by the function `C_a(t) = t^2 - 2t + 5`. The cost of running the second motor is given by `C_b(t) = 3t + 2`. Which function gives the total cost of running both motors?

A. 

`C(t) = 3t^3 - 6t^2 + 15t`

B. 

`C(t) = 2t^2 - 4t + 10`

C. 

`C(t) = t^2 + t + 7`

D. 

`C(t) = 3t^3 + 6t^2 - 15t`

Answer 1

To add polynomials distribute to eliminate parentheses then combine like terms.

This gives choice C as the answer.