We are given a rectangle ABCD
Recall that a rectangle is a quadrilateral in which all angles are right angles (90°)
Each pair of interior angles are supplementary. The two right angles add to a straight angle which means that the opposite sides of a rectangle are parallel.
In quadrilateral ABCD, if m∠A = m∠B = m∠C = m∠D = 90° then AB || DC and AD || BC
Hence, a rectangle is also a parallelogram.
Option B is the correct answer.
