What is the average cost, denoted as /bar (C)(x), of manufacturing x vests in one given day? The cost function is given by C(x) = 0.05x^2 + 10x + 180. Which of the following options correctly represents the average cost /bar (C)(x)?
A) /bar (C)(x) = 0.05x^2 + 10x + 180
B) /bar (C)(x) = 0.05x^2 + 10x
C) /bar (C)(x) = 0.05x^2 + 180
D) /bar (C)(x) = 10x + 180