Option C is not true.
Since △ABC ~ △EDF, the correct correspondence is A↔E, B↔D, C↔F. So the correct angle equalities are ∠A = ∠E, ∠B = ∠D, ∠C = ∠F — not ∠A = ∠D.
Answer: C
In △ABC ~ △EDF, the order of vertices gives the correspondence: A↔E, B↔D, C↔F. The textbook explicitly states that similarity must be expressed using correct correspondence of vertices (e.g., "we cannot write △ABC ~ △EDF" for a different pairing). Options A, B, and D all hold using the correct ratios (AB/ED, AC/EF, etc.); only C incorrectly states ∠A = ∠D instead of ∠A = ∠E.