The answer is either expansive or respective if I'm not mistaken. I hope this helps! :)
I cant see the rest of the passage, but im taking a guess that it is no.2!
The Principle Of Matter. What he means by this is that he knows he should not have done what he did. (Or so I have found out. Hope this helps!) :0
Most people are comfortable with the idea of a noun, but they may not feel so confident when it comes to the noun clause. A noun clause is a group of words acting together as a noun. These clauses are always dependent clauses. That is, they do not form a complete sentence. Take a look at some sample sentences containing noun clauses to understand their purpose and function.