What problem does Grover's algorithm solve?

Question: What is Grover's algorithm mainly used for? A) Searching an unstructured space with quadratic speedup B) Sorting a classical array in linear time C) Measuring all qubits without collapse D) Copying arbitrary quantum states Correct: A Explanation: Grover's algorithm is used for unstructured search. It can find a marked item using approximately the square root of the number of possibilities, giving a quadratic speedup over brute-force classical search. Topic: quantum computing / Grover's algorithm