The following diagram shows a logic gate?

Answer: The circuit is the Exclusive-NOR gate (XNOR).

How to identify from the diagram:

• The gate outline looks like an OR gate with an extra curved input line just before the gate — that extra curve denotes exclusive-OR (XOR) behavior.

• There is a small circle (inversion bubble) at the output — that indicates the output is inverted. XOR followed by inversion gives XNOR.

Boolean expressions:

• XNOR as complement of XOR: Y = (A ⊕ B)'

• Canonical form: Y = A·B + Ā·B̄

Therefore the correct answer is the Exclusive-NOR gate (XNOR).