Answer
Rank in descending order: B, C, A.
Work Step by Step
Take $s$ to be the diameter of the object, $\theta$ to be the angle the object subtends, and $r$ to be the distance from the object to the observer. We have $$r=\frac{s}{\theta}$$
For an object with $s=d$ and $\theta=\theta_0$, we have $r=d/\theta_0$
- Object A: $$r_A=\frac{4d}{2\theta_0}=2r$$
- Object B: $$r_B=\frac{3d}{\frac{\theta_0}{2}}=6r$$
- Object C: $$r_C=\frac{\frac{d}{2}}{\frac{\theta_0}{8}}=4r$$
To rank in descending order: B, C, A.
