If the marginal cost is given by function MC(x) = $\frac{x}{2}+3$ Which of the following can be the cost function? A. $\frac{x^2}{4}+3$ B. $\frac{x^2}{4}+3 x+5$ C. $\frac{x^2+12 x-1}{4}$ D. $\frac{1}{2}$ E. $\frac{x^2}{4}-3 x-1$ Choose the correct answer from the options given below:

A only D only B and C only E only

A only

The correct answer is Option () -