What does the block-encoding normalization α control?

Question: A unitary U is an α-block encoding of a matrix A. Which interpretation is most accurate? A) A selected block of U equals A/α, so singular-value transformations act on the normalized spectrum B) U equals exp(iαA), so α is an evolution time C) α is the number of ancilla qubits required by the encoding D) α guarantees that A is Hermitian and positive semidefinite Correct: A Explanation: In an α-block encoding, the matrix A appears inside a larger unitary after normalization by α. This scaling affects algorithmic complexity and the domain on which polynomial transformations act. Topic: advanced quantum computing / block encoding / normalization