smc

The water tower holds $\frac{100000}{0.1}=1000000$ times more water than Logan's miniature. The volume of a sphere is: $V=\frac{4}{3}\pi r^3$. Since we are comparing the heights (m), we should compare the radii (m) to find the ratio. Since, the radius is cubed, Logan should make his tower $\sqrt[3]{1000000}=100$ times shorter than the actual tower. This is $\frac{40}{100}=\boxed{0.4}$ meters high, or choice $\text{(C)}$. Note: The fact that $1\text{ L}=1000{\text{ cm}}^3$ doesn't matter since only the ratios are important.