Option D:
Squares are rectangles
Solution:
To find which statement is true:
Option A: Rhombi are squares
Interior angles of rhombus are not always 90°.
But interior angles of a square are always 90°.
So rhombi are not always squares.
It is not true.
Option B: Parallelograms are rectangles
Interior angles of parallelograms are not always 90°.
But interior angles of a rectangles are always 90°.
So parallelograms are not always rectangles.
It is not true.
Option C: Rectangles are squares
Opposite sides of rectangle are congruent.
All sides of square are congruent.
So rectangles are not squares.
It is not true.
Option D: Squares are rectangles
In square all sides are congruent, so opposite sides are also congruent with four right angles.
In rectangle opposite sides are congruent with four right angles.
Therefore all squares are rectangles.
It is true.
Option D is the correct answer.