In a proof that the diagonals of rectangle ABCD are congruent, the statements you're referring to establish the congruence of the corresponding sides and angles of triangles formed by the diagonals and the sides of the rectangle.
The correct statement that would logically follow after establishing that line AD ≅ line BC, line AB ≅ line AB, and angle DAB ≅ angle CBA would be:
B. triangle DAB ≅ triangle CBA
This is because the sides and angles established lead to the conclusion that these two triangles (DAB and CBA) are congruent, which is a necessary step in proving that the diagonals (AC and BD) of the rectangle are congruent.