Assertion (A) When an ideal gas is compressed adiabatically, its...

Options

1. A$\mathrm{A}$ and $\mathrm{R}$ and true and $\mathrm{R}$ is correct explanation of A.
2. B$\mathrm{A}$ and $\mathrm{R}$ are true but $\mathrm{R}$ is not correct explanation of $A$.
3. C$A$ is true and $R$ is false.
4. D$\mathrm{A}$ is false and $\mathrm{R}$ is true.