Question

Which figure must be a square?

A.
a parallelogram with four congruent sides





B.
a quadrilateral with four right angles





C.

a quadrilateral with congruent sides



D.
a rhombus with four right angles

Answer 1

4 right angels= A square, therefore D is correct. 

Answer 2

A is describing either a rectangle, rhombus, or square, so that's not it. B is the same, C is also a possible rhombus, and so D is the correct answer as a square.