For which of the sets of a, is the statement, “The difference between the roots of the equation $x^2+ax+1 =$ is less than $\sqrt 5”$ true?

Question

$\begin {array} {1 1} (A)\;(-3,\infty) & \quad (B)\;(3,\infty) \\ (C)\;(-\infty, -3) & \quad (D)\;(-3, 3) \end {array}$