What is a Bloch sphere?

Question: What is the Bloch sphere used for? A) Counting the number of shots B) Visualizing the state of a single qubit C) Storing a quantum program permanently D) Measuring two qubits at once Correct: B Explanation: The Bloch sphere is a geometric way to visualize a single-qubit state. Single-qubit gates can often be understood as rotations on this sphere. Topic: quantum computing / Bloch sphere / visualization