The explosive- trinitrotoluene- tnt- c6h3n306- has the same

The explosive, trinitrotoluene, TNT, C6H3N306, has the same proportion of:

a. N to H atoms as does NH3

b. H to O atoms as does H20

c. N to O atoms as does NO2

d. C to H atoms as does C3H6

e. C to O atoms as does CO2.

I know the correct answer is C. But I need someone to help explain how to do this problem for me. Thanks!