1.It's A because 'as' should have been used, meaning 'which'. 'I will refuse his demands which are outrageous '.
2.But' unless' has nothing to do with the context provided in C because 'until' should have fitted here.
the word that needs correcting is "do" the right answer is supposed to be "with"
You study the correct way for the right answers to all problems. Sometimes we think we are right, and then findout we where wrong. Always ask questions and always double check.
Knowing the formal charge on a particular atom in a structure is an important part of keeping track of the electrons and is important for establishing and predicting the reactivity. The formal charge on an atom in a molecule reflects the electron count associated with the atom compared to the isolated neutral atom.
Honestlty a pronoun can be placed anywhere.
Just depends were the antecendt is.