Dipole moment of ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_3,{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH},{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{NH}}_2$ will be order

More is the electronegativity difference, higher the polarity and hence, the dipole moment.
Thus, correct order of dipole moment is I < III < II.