Step 1: Analyze the circuit structure.
- The given circuit consists of two NOT gates applied to \( A \) and \( B \), followed by two AND gates whose outputs feed into gate \( G \).
- The final truth table indicates that \( Y \) is high for \( (A, B) = (0,0) \) and \( (1,1) \), but low otherwise.
Step 2: Identify the logical expression.
Observing the output pattern, we recognize it corresponds to the NOR operation:
\[
Y = \overline{A + B}.
\]
Step 3: Select the appropriate gate.
- The only logic gate that produces \( Y = \overline{A + B} \) is the NOR Gate.
- Thus, the correct choice for gate \( G \) is a NOR gate.
Thus, the answer is \( \boxed{\text{NOR Gate}} \).