In parallelogram ABCD, which angle is congruent to ?
Let us draw the parallelogram to better understand the problem.
As you can see from the above figure,
∠ABC and ∠CDA are congruent. (drawn in black color)
Also, ∠BCD and ∠DAB are congurent. (drawn in red color)
This means that the opposite angles are congruent in a parallelogram.
Therefore, the correct answer is option C
∠ABC and ∠CDA are congruent.