Let $\alpha$ and $\beta$ be the roots of equation $p x^{2}+q x+r-0, p \neq 0 .$ If $p, q, r$ are in A.P. and $\frac{1}{\alpha}+\frac{1}{\beta}=4$, then the value of $|\alpha-\beta|$ is
$|2014|$
(A) $\frac{\sqrt{61}}{9}$
(B) $\frac{2 \sqrt{17}}{9}$
(C) $\frac{\sqrt{34}}{9}$
(D) $\frac{2 \sqrt{13}}{9}$