Which one is the correct option for the two different thermodynamic processes ?

Option (a) is wrong; since in adiabatic process $\mathrm{V}\ne$ constant.

Option (b) is wrong, since in the isothermal process
T= constant

Option (c) & (d) matches isotherms & adiabatic formula :

$T{V}^{\mathit{\gamma }\mathit{-}\mathit{1}}= \mathrm{constant} \&\frac{T^{\gamma }}{p^{\gamma -1}}=\mathrm{constant}$