Premises: if a quadrilateral has opposite sides that are parallel, then it is a parallelogram. a rhombus is a quadrilateral where the opposite sides are parallel. conclusion: a rhombus is a parallelogram. which statement best describes this argument? the argument is valid by the law of syllogism. the argument is invalid because the conclusion does not follow the premises. the argument is valid by the law of detachment. the argument is invalid because the premises are not true.