Which statement is true about this argument? premises: if a quadrilateral is a square, then the quadrilateral has four right angles. quadrilateral jklm has four right angles. conclusion: quadrilateral jklm is a square. the argument is not valid because the conclusion does not follow from the premises. the argument is not valid because the premises are not true. the argument is valid by the law of detachment. the argument is valid by the law of syllogism.