I was doing this question, but it tells me one of the option I selected was wrong.
The second option I thought it means "all of the things in A is not in B" indicates that "there exists something in A that is not in B"
The last option I thought means "not all things in A are in B" indicates that "there exists something in A that is not in B"
Both make sense to me, please help explain which one I selected is wrong. Also is there any that I haven't selected is correct?