Geometry

Question Analysis：
This question is about applying the AAS congruence postulate.
The main focus is to identify non - included sides given two pairs of congruent angles.

Key Concept Explanation：
AAS requires two angles and a non - included side to be congruent.
Here, with ∠A = ∠D and ∠B = ∠E, we need non - included sides.
Step - by - Step Solution
Given ∠A = ∠D and ∠B = ∠E.
Analyze sides:
BC in ∆ABC is non - included for ∠A and ∠B, and EF in ∆DEF is non - included for ∠D and ∠E, so BC = EF.
AC in ∆ABC is non - included for ∠B and ∠A, and DF in ∆DEF is non - included for ∠E and ∠D, so AC = DF.

Option Analysis：
Option A: AB = DE is incorrect as AB is an included side.
Option B: BC = EF is correct as it's a non - included side.
Option C: AC = DF is...