Arrange following compounds in decreasing order of their dipole moment.
`underset("I")(CH_(3)-CH_(2)-NO_(2))" "underset("II")(CH_(3)-CH_(2)-NH_(2))" "underset("III")(CH_(3)-CH_(2)-F)" "underset("IV")(CH_(3)-CH_(2)-C-=N)`
A. `IVgtIIIgtIgtII`
B. `IVgtIgtIIIgtII`
C. `IgtIIIgtIVgtII`
D. `IgtIVgtIIIgtII`