Answer : (d) 0
Given, p(a + (p – 1) d) = q (a + (q – 1)d), where a and d are the first term and common difference of the A.P.
⇒ (p – q)a = (q2 – q – p2 + p)d
⇒ – (q – p)a = (q – p) ((q + p) – 1) d
⇒ – a = ((q + p) – 1)d
⇒a + ((p + q) – 1)d = 0
⇒ tp + q = 0.