The shape can only be a rectangle! A rectangle is a four-sided 2-dimentional figure, where every angle is a right angle, opposite sides are parallel, but the 4 sides are NOT equal.
Yes, it can... but does not have to. A parallelogram is a four-sided plane figure with opposite sides parallel. So as long as it has opposite sides that are parallel, it is a parallelogram.
A rhombus is a 4 equal sided quadrilateral with opposite parallel sides and equal opposite acute angles and equal opposite obtuse angles that all add up to 360 degrees.