The correct option is (C): 80.
HCF of (ap – 1) and (aq – 1) will be HCF (ahcf (p, q) – 1)
Here, we need to find the HCF of (8125 – 1) and (274 – 1), which can
further be deducted as HCF of (3100 – 1) and (312 – 1).
Thus, the required HCF will be (3hcf (100, 12) – 1), i.e, 34 – 1 or 80.