a
Mass of \(6.023 \times 10^{23}\) atoms of oxygen \(= 16\,g\)

Mass of one atoms of oxygen \( = \frac{{16}}{{6.023 \times {{10}^{23}}}} = 2.66 \times {10^{ - 23}}\,g\)

Mass of \(6.023 \times 10^{23}\) atoms of nitrogen \(= 14\,g\)

Mass of one atom of nitrogen 

\( = \frac{{14}}{{6.023 \times {{10}^{23}}}} = 2.32 \times {10^{ - 23}}\,g\)

Mass of \(1 \times 10^{10}\) mole of oxygen \(= 16 \times 10^{-10}\)

Mass of \(1\) mole of copper \(= 63\,g\)

Mass of \(1\) mole of oxygen \(= 16\,g\)

Mass of \(1 \times 10^{-10}\) mole of copper

                                                      \(= 63 \times 1 \times 10^{-10}\)

                                                      \(= 63 \times 10^{-10}\)

So, the order of increasing mass is

\(II < I < III < IV\)