PLZ HELP I AM STUCK!
 Which statement completes the syllogism?
 If a polygon is a square, then it has four congruent sides.If a polygon has four congruent sides, then it is a rhombus.
 Therefore, ... 
 A: If a polygon is a square, then it is a rhombus
 B: If a polygon is a rhombus, then it is a square
 C: If a polygon is a rhombus, then it is a parallelogram
 D: If a polygon has four congruent sides, then it is a square