answer choice b
CPCTC stands for “Corresponding Parts of Congruent Triangles are Congruent”
This means if two triangles are proven to be congruent their parts, whether sides or angles will be congruent.
the two angles, BTA and ATC share the same vertex, T (the vertex is the middle letter) [vertex is where the two lines for the angles meet]
since the two triangles are congruent, and the angle that is mentioned is a shared vertex, that means the two angles are congruent.