Characterization gives us insight into the character's which builds conflict.
antagonist
exposition
motivation
internal conflict

Characterization gives us insight into the character's motivation which builds conflict.The motivation of the character reveals his background and true intent. In this regard, we can characterize the character whether he is good or bad due to reasons

The correct answer is motivation.
Motivation is what makes a character do a particular thing within a novel, what urges him or her to do (or not do) something. So, a character's motivation can bring about a conflict if what they want to do doesn't align with what the other characters want. 
An antagonist is a bad character; exposition is the introduction; internal conflict doesn't need to escalate into an external conflict, whereas motivation might.

Can you give the sentences?