Which of these sentences is always true for a parallelogram?A.All sides are congruent.B. All angles are congruent.c.The diagonals are congruent.D. Opposite angles are congruent.​

Answer:The sentence which is always true for a parallelogram is:      D:  Opposite angles are congruentStep-by-step explanation:Parallelogram--A parallelogram is a polygon with 4 sides such that it has 2 pair of opposite sides which are parallel.The properties of parallelogram are as follows:Opposite sides are congruentOpposite angles are congruent.Diagonals of a parallelogram bisect each other.Consecutive angles are supplementary.               The correct answer is: Option: D.