which of the following statements are correct? a. if one interior angle of a parallelogram is a right angle, then the parallelogram must be a rectangle. b. if two diagonals of a rectangle are perpendicular, then the rectangle must be a square. c. if two diagonals of a rhombus are equal, then the rhombus must be a square. d. if one interior angle of a rhombus is a right angle, then the rhombus must be a square. e. if two diagonals of a parallelogram are equal, then the parallelogram must be a rectangle. enter all correct options as a list of letters, separated by commas.