In the circuit, the logical value of A = 1 or B = 1 when potential...

When both $A$ and $B$ have logical value ‘$1$’ both diode are reverse bias and current will flow in resistor hence output will be $5$ volt i.e. logical value ‘$1$’.

In all other case conduction will take place, hence output will be zero volt i.e. logical value ‘$0$’. So truth table is

$\begin{cases}A & B & Y \\ 0 & 0 & 0 \\ 0 & 1 & 0 \\ 1 & 0 & 0 \\ 1 & 1 & 1\end{cases}$

Thus, given circuit is equivalent to an AND gate.