Could any one help me out explaining why (C) is not the right answer for question 4?

It seems like McBride and Leggett both are talking about automobile safety for me.

karin.yoo wrote: 3. If it is not the case that both A and B are present, then C is. My interpretation) A or B --> C, ~A and ~B --> C Contrapositive) ~C --> ~A and ~B, ~C --> A or B maryadkins replied : I can't imagine you'd ever actually see this. But if you do, it's: ~A or ~B --> C ~...