JEE Main 2026 Apr 8 Shift 2, Physics Q20: Logic Gates

The upper branch is $A\cdot B$, the lower branch takes $\bar{A}$ (via the inverter on the $A$ line) and $B$ to give $\bar{A}\cdot B$. The OR of these is:

$Y=A\cdot B+\bar{A}\cdot B=(A+\bar{A})\cdot B=1\cdot B=B$.

So the output simply equals $B$ for all $t$. Matching to the option whose waveform mirrors $B$ identifies option (2).