What determines the precision of standard QPE?

Question: Suppose an exact eigenstate of U is available and an m-qubit evaluation register is used in standard Quantum Phase Estimation. Which description is most accurate? A) The phase precision scales as O(1/m) because each evaluation qubit contributes one independent sample B) The binary resolution scales as O(2⁻ᵐ), obtained using controlled powers of U followed by an inverse QFT C) The precision is independent of m but the success probability approaches one exponentially D) The inverse QFT increases precision from O(1/m) to O(1/m²) without requiring powers of U Correct: B Explanation: Controlled applications of U raised to powers of two encode increasingly fine phase information in the evaluation register. The inverse QFT converts these relative phases into a binary approximation, giving resolution proportional to 2⁻ᵐ, apart from success-probability considerations. Topic: advanced quantum computing / phase estimation / QFT