JEE Math Practice Question

Let $$\alpha $$ and $$\beta $$ be the roots of equation $$p{x^2} + qx + r = 0,$$ $$p \ne 0.$$ If $$p,\,q,\,r$$ in A.P. and $${1 \over \alpha } + {1 \over \beta } = 4,$$ then the value of $$\left| {\alpha - \beta } \right|$$ is :

1. A.$${{\sqrt {34} } \over 9}$$
2. B.$${{2\sqrt 13 } \over 9}$$
3. C.$${{\sqrt {61} } \over 9}$$
4. D.$${{2\sqrt 17 } \over 9}$$