Read number 4 on this website.
... my bad. Well. originally my thoughts were CH4 becuase that compound has the least attractive forces between the bonds
Carbon electornegativity = 2.5
Hydrogen electronegativity = 2.1
so 2.5 - 2.1= 0.4 EN
p.s. It's Extra Credit, not Homework, but I get what you mean. haha