Answer :- It cannot be determined from the information given.
Explanation:-
Given:- Quadrilateral RSTU has one pair of opposite parallel sides and one pair of opposite congruent sides
The characteristics of a parallelogram :-
- The opposite sides are parallel.
- The opposite sides and angles are equal.
- The diagonals are perpendicular bisectors.
Thus the given information is not enough to determine that whether quadrilateral RSTU a parallelogram or not.