In question [IV] how is it wrong,i mean the subset will still remain even after subtraction of A-B so it has to be true?

In question [V] is it false because they are elements not subset?

Here in question [VII] its true? how while in question IV the answer was false? am i missing something here?

[![enter image description here](https://i.stack.imgur.com/FBe4V.png)](https://i.stack.imgur.com/FBe4V.png)

[sub](https://i.stack.imgur.com/60OFM.png)