The graph below shows a portion of the curve defined by the quartic polynomial P(x)=x^{4}+a x^{3}+b x^{2}+c x+d. Which of the following is the smallest?

**Answer Choices**

A. P(-1)

B. $The product of the zeros of $P$$

C. $The product of the non-real zeros of $P$$

D. $The sum of the coefficients of $P$$

E. $The sum of the real zeros of $P$$