What is symmetry tapering in VQE?

Question: What is the purpose of symmetry tapering in VQE-style problems? A) To increase the Hamiltonian dimension B) To reduce the number of qubits by exploiting conserved symmetries C) To replace the classical optimizer with measurement D) To make all Pauli strings non-commuting Correct: B Explanation: If a Hamiltonian has known symmetries, those symmetries can sometimes be used to reduce the effective qubit count. This can make VQE simulations and hardware runs more efficient. Topic: quantum computing / VQE / symmetry reduction