If in an AP , $\;a_{n}\;$ denotes the $\;n^{th}$ term and $\;a_{p}=\frac{1}{q}$ and $\;a_{q}=\frac{1}{p}$ the root of the equation

Question

$(a)\;a_{p}\qquad(b)\;a_{q}\qquad(c)\;a_{pq}\qquad(d)\;a_{p+q}$