If $(x+a)$ is the HCF of $x^2+px+q$ and $x^2+lx+m$ then the value of $'a'$ is given by

Question

$\begin{array}{1 1}\large\frac{p-l}{q-m}\\\large\frac{q-m}{p-l}\\\large\frac{l+p}{q+m}\\\large\frac{q+m}{p+l}\end{array} $