Geometry

Question Analysis:
This question assesses knowledge of valid triangle congruence postulates, including ASA and its alternatives.

Key Concept Explanation:
ASA (B): Two angles + included side → Congruence guaranteed.
AAS (A): Two angles + non-included side → Also valid (equivalent to ASA via Triangle Angle Sum).
SSS (D): Three sides → Valid.
SSA (C): Not valid ("Ambiguous Case").

Step-by-Step Solution:
Review congruence postulates:
Valid: ASA, AAS, SSS, SAS, HL.
Invalid: SSA, AAA.
Evaluate options:
(A) AAS → Valid.
(B) ASA → Valid.
(C) SSA → Invalid.
(D) SSS → Valid.

Option Analysis:
Why (A) is correct: AAS is ...