A quadrilateral must be a parallelogram if one pair of its opposite sides are a)congruent only b)parallel and other two pair of opp sides are congruent c) congruent and parallel d) parallel only

There are six important properties of parallelograms to know:

1. Opposite sides are congruent (AB = DC).
2. Opposite angels are congruent (D = B).
3. Consecutive angles are supplementary (A + D = 180°).
4. If one angle is right, then all angles are right.
5. The diagonals of a parallelogram bisect each other.
6. Each diagonal of a parallelogram separates it into two congruent.                                                                            Option -c is correct