What does quantum interference do?

Question: How is quantum interference useful in quantum algorithms? A) It prevents qubits from being measured B) It copies the correct answer many times C) It can amplify useful outcomes and cancel unwanted outcomes D) It turns every circuit into a classical circuit Correct: C Explanation: Quantum interference allows probability amplitudes to combine constructively or destructively. Algorithms use this to increase the chance of measuring useful answers. Topic: quantum computing / interference / algorithms