Correct Answer - A::D
`a.` In nitrobenzene, small angle so high dipole moment `(mu).`
`b.`
`(` low `mu`, distance is less, due to double bond `)`
`[` High `mu`, more charge separate and large distance `(` single bond, more bond length `),` since `mu=qxxd(` charge `xx` distance `).]`
`c.`
`d.`