What does the normalization factor in block encoding mean?

Question: A unitary U is described as an α-block encoding of a matrix A. Which interpretation is correct? A) Every eigenvalue of U is α times an eigenvalue of A B) Measuring the ancillas returns A as a classical matrix with probability 1/α C) A designated block of U represents A/α, so algorithms operate on singular values scaled by α D) U is an approximation to e^(−iαA) whose error is bounded by 1/α Correct: C Explanation: Block encoding embeds a normalized version of a generally nonunitary matrix inside a larger unitary. The normalization α determines the scale of the embedded singular values and therefore affects polynomial approximations and algorithmic complexity. Topic: advanced quantum computing / block encoding / QSVT