Why is the T gate important?

Question: Why is the T gate important in the Clifford+T gate set? A) It is only used for measurement B) It supplies a non-Clifford operation needed for universal quantum computation C) It deletes errors automatically D) It replaces every two-qubit gate Correct: B Explanation: Clifford gates plus a suitable non-Clifford gate such as T form a universal gate set. The T gate is therefore central to fault-tolerant quantum computing and resource estimation. Topic: quantum computing / T gate / universal gate sets