Question

The figure below shows rectangle ABCD with diagonals segment AC and segment BD:

A rectangle ABCD is shown with diagonals AC and BD.
Zinnia wrote the following proof to show that the diagonals of rectangle ABCD are congruent:

Zinnia's proof:
Statement 1: Rectangle ABCD is given
Statement 2: segment AD ≅ segment BC because opposite sides of a rectangle are congruent
Statement 3: segment DC ≅ segment DC by the reflexive property of congruence
Statement 4: Angles ADC and BCD are both right angles by definition of a rectangle
Statement 5: Angles ADC and BCD are congruent because all right angles are congruent
Statement 6:
Statement 7: segment AC ≅ segment BD by CPCTC

Which statement below completes Zinnia's proof?

Triangles ADC and BCD are congruent (by ASA postulate)
Triangles ADC and BCD are congruent (by SAS postulate)
Triangles ADC and CBA are congruent (by ASA postulate)
Triangles ADC and CBA are congruent (by SAS postulate)