Answer
Choice D.
Work Step by Step
Apply the thin-lens formula. We are told that a lens with $\frac{1}{f}=-6.0D$ would correct the frog’s distance vision. This lens would take an object at infinity and create a virtual image at the near point.
$$\frac{1}{s}+\frac{1}{s’}=\frac{1}{f}$$
$$\frac{1}{\infty}+\frac{1}{s’}=-6.0m^{-1}$$
$$s’=-0.17m$$
The frog can clearly see an object that is 17cm away.
