Answer :

 C .. ectronegativity values for each of the atoms but if you didn't know these you can just look at your periodic table and see where they are in relation to each other
toyboxthe
 A) N is more polar because of it electron negativity charge ex. N electron negativity charge is 3.0 and H is 2.1 
 B) C is more polar...electron negativity for C is 2.5 AND H is 2.1 
 C)O is more polar dues to it electron negativity charge being greater that hydrogen 
 D)H and H are both non polar because they cancel each other out due to the face the both share the electron negativity evenly