Answer:
7t^2 + 3t + 6
Explanation:
The computation of the expression is shown below:
The function describes the manufacturing cost of product A.
a(t) = 5t + 2
Likewise for product B, the manufacturing cost function is
b(t) = 7t^2 - 2t + 4
So if we combined these two, the equation would be presented below
= a(t) + b(t)
= 5t + 2 + 7t^2 - 2t + 4
= 7t^2 + 3t + 6
Hence, the correct option is D