Question 592846
The answer is choice A since this is a valid use of the constructive dilemma property.



Choice B uses modus tollens in a correct way, but you have to use double negation to do it properly. So more than one step is used. So choice B is out



Choice C uses the hypothetical syllogism, but it's completely incorrect. So choice C is out.



Choice D uses De Morgan's Law, which is valid, but it skips a step by leaving out double negation again...so choice D is out.



Choice E is correct, but commutation must be used first. So choice E is out.



So again, the answer is choice A.