SOMEONE PLEASE HELP!!

Answer:
a
Step-by-step explanation:
B isn't the answer because diagonals of rectangles dont form perpendicular angles only quadralterials are squares and rhombus, and kites.
C isn't the answer because multiple quadralterials have equal alternate interior angles like Rhombus and most trapezoids.
D isn't the answer because it works for trapezoid and rhombus.
While A applies for square and rectangle, we already know it a rectangle since there is a pair opposite sides are congruent.