Use the definition of a parallelogram to complete the biconditional statement.

A parallelogram is a quadrilateral with two pairs of parallel sides.

A quadrilateral is a parallelogram _[blank]_.

Which answer correctly fills in the blank in the previous sentence?

if it has only two pairs of parallel sides
if and only if it has two pairs of parallel sides
because it has only four sides and two of them are parallel
if it has two pairs of parallel sides and is a polygon