JEE Main 2025 Apr 4 Shift 2, Chemistry Q18: Mechanism of Some Important Reactions of Alkenes

The substrate is a diene with a strained, fused-ring framework. Protonation occurs at the alkene carbon that gives the more stable carbocation.

Adding $H^{+}$ to one of the alkene carbons generates a tertiary carbocation at the ring-junction carbon (the most substituted position), since that carbon is attached to three ring carbons.

Bromide ion then attacks this tertiary cation. The bromine therefore ends up on the ring-junction (tertiary) carbon. This is the Markovnikov major product, with no extra H drawn on the Br-bearing carbon because it is fully substituted by ring atoms.

$\therefore$ Option (2) is the major product.