The major products A and B in the following reaction sequence are

Concept: Triflic anhydride is useful for converting ketones into enol triflates. In a representative application, is used to convert an imine into a NTf group. It will convert phenols into a triflic ester, which enables cleavage of the C-O bond.

Hydrazine is a powerful, endothermic reducing agent.

Explanation: Triflic anhydride first get attached to the ring and then lone pair of hydrazine will attack to triflate carbon followed by proton transfer and then ring cyclization.

It is Wolf Kishner clemmensen reaction.

Conclusion: option A is correct.