$A$ body cools in a surrounding which is at a constant temperature of $\theta_0$. Assuming that it obeys Newton's law of cooling,its temperature $\theta$ is plotted against time $t$. Tangents are drawn to the curve at the points $A(\theta = \theta_1)$ and $B(\theta = \theta_2)$. These tangents meet the time-axis at angles $\alpha_1$ and $\alpha_2$ as shown in the graph. Then:

• A
  $\frac{\tan \alpha_1}{\tan \alpha_2} = \frac{\theta_2}{\theta_1}$
• B
  $\frac{\tan \alpha_1}{\tan \alpha_2} = \frac{\theta_1}{\theta_2}$
• C
  $\frac{\tan \alpha_1}{\tan \alpha_2} = \frac{\theta_1 - \theta_0}{\theta_2 - \theta_0}$
• D
  $\frac{\tan \alpha_1}{\tan \alpha_2} = \frac{\theta_2 - \theta_0}{\theta_1 - \theta_0}$