Arectangle is always an example of a:
rhombus
ii. parallelogram
iii. square
iv. trapezoid

I believe the correct answer from the choices listed above is option II. A rectangle is always an example of a parallelogram. It  is a simple (non-self-intersecting) quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure.