When the temperature of a body increases from $T$ to $T+\Delta T$, its moment of inertia increases from $I$ to $I+\Delta I$. If $\alpha$ is the coefficient of linear expansion of the material of the body, then $\frac{\Delta I}{I}$ is (neglect higher orders of $\alpha$ ).

• A
  $\alpha \Delta T$
• B
  $2 \alpha \Delta T$
• C
  $\frac{\Delta T}{\alpha}$
• D
  $\frac{2 \alpha}{\Delta T}$