Which statement is true about this argument? premises: if two angles form a linear pair, then they are supplementary. if two angles are supplementary, then the sum of their measures is 180°. conclusion: if two angles form a linear pair, then the sum of their measures is 180°. a) the argument is not valid because the premises are not true. b) the argument is not valid because the conclusion does not follow from the premises. c)the argument is valid by the law of syllogism. d)the argument is valid by the law of detachment.