What is a logical qubit?

Question: What is a logical qubit? A) A measured classical bit B) A qubit that exists only in a textbook C) A protected qubit encoded using multiple physical qubits D) A gate that flips two qubits at once Correct: C Explanation: A logical qubit is an encoded qubit protected by quantum error correction. It is built from multiple noisy physical qubits to represent more reliable quantum information. Topic: quantum computing / logical qubits / error correction