Why is simulating many qubits hard classically?

Question: Why does classical simulation of general quantum states become hard as qubit count increases? A) Because classical computers cannot store numbers B) Because measurement is not allowed in simulators C) Because the state vector size grows exponentially with the number of qubits D) Because all quantum gates are random Correct: C Explanation: A general n-qubit state needs 2^n complex amplitudes. As n grows, the memory and computation required for exact statevector simulation grow exponentially. Topic: quantum computing / simulation / complexity