B ............ is the answer,
When oxygen has an electronegativity of 3.5, and carbon has an electronegativity of 2.5, then the oxygen atom would have a slightly negative charge. The oxygen atom in the carbon monoxide molecule would pull more electrons to its side since it has higher electronegativity making it slightly negative and the carbon would have a slightly positive charge as it would contain less electrons. This results to the formation of a polar molecule. A polar molecule is made when the molecule contains a slightly positive end and a slightly negative end. It would have a net dipole which is a result of the partial opposing charges in the molecule.
The balanced equation given is:
4NH3 + 3O2 .....> 2N2 + 6H2O
From this equation, we can note that 4 moles of NH3 are required to produce 2 moles of N2.
Therefore, the mole ratio of NH3 to N2 is 4:2 which can be simplified into 2:1
I would expect silane because all the rest have an overall dipole movement