a
\(\Delta Q\,\, = \,\,\Delta U + \Delta W\,\, \Rightarrow \,\,\frac{{\Delta W}}{{\Delta Q}}\,\, = \,\,1 - \frac{{\Delta U}}{{\Delta Q}}\,\, = \,\, - \frac{{\mu {C_v}dT}}{{\mu {C_p}dT}}\)
\( \Rightarrow \,\,\frac{{\Delta W}}{{\Delta Q}}\,\, = \,\,1 - \frac{{{C_V}}}{{{C_P}}}\,\, = \,1 - \frac{3}{5}\,\, = \,\,\frac{2}{5}\,\, = \,\,0.4\)