Your eyeball is 2.10 cm from the cornea to the retina. A book held 30 cm from your eyes produces an image 2.26 cm from the entrance to the image location. Which answer below is closest to the focal length of the cornea-lens system?
(a) $+1.96 \mathrm{cm} \quad(\mathrm{b})+2.10 \mathrm{cm} \quad(\mathrm{c})+2.26 \mathrm{cm}$ (d) $+2.42 \mathrm{cm} \quad(\mathrm{e})+27.90 \mathrm{cm}$