Quadrilateral RSTU has one pair of opposite parallel sides and one pair of opposite congruent sides as shown.

Quadrilateral R S T U is shown. Sides R U and S T are parallel. The lengths of sides R S and U T are congruent.

Based on the given information, which statement best explains whether the quadrilateral is a parallelogram?

It cannot be determined from the information given.
It is not a parallelogram because the congruent sides cannot be parallel.
It is not a parallelogram because the parallel sides cannot be congruent.
It is a parallelogram based on the single opposite side pair theorem.