$2 \cdot 110$ To make $p=x^{4}+6 x^{3}+11 x^{2}+3 x+31$ a perfect square of an integer, the number of integer values of $x$ is
(A) 4.
(B) 3.
(C) 2.
(D) 1.
(E) 0.
(16th American High School Mathematics Examination, 1965)