(A) The boiling point of nitro-alkanes is higher than their corresponding alkyl nitrites.
(R) Nitro-alkanes show strong dipole-dipole interaction.

Nitro alkanes are having higher dipole moments due to high polar nature. Polar nature is due to full positive charge on nitrogen and one - half negative charge on each oxygen atom.Due to greater polar nature nirro alkanes are having strong inter molecular forces than nitrito alkanes.Boiling point of nitro alkanes are higher than corresponding nitrito alkanes.