To prove that quadrilateral ABCD is a parallelogram, we can use the property of opposite sides being congruent. In a parallelogram, one of the key characteristics is that both pairs of opposite sides are congruent.
Since it is given that two sets of opposite sides are marked as congruent, we have:
- AB ≅ CD (one pair of opposite sides).
- BC ≅ AD (the other pair of opposite sides).
According to the properties of quadrilaterals, if both pairs of opposite sides are congruent, then the quadrilateral must be a parallelogram.
Therefore, the correct response is:
- Opposite sides of the figure are congruent.