STATEMENTS KLASUN What could be the final reason in the proof below? ASA HL SAS CPCTC

In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data
Diagram
Step 02:
We must apply the properties of parallel and transversal lines.
Statements Reasons
AB || CD , AB = CD 1. Given
∠ ABD = ∠ CDB 2. Alternate interior angles
BD = DB 3. Reflexive Property
ΔABD = ΔCBD 4. Side-angle-side SAS
That is the full solution.