Find the Radius of a Star Image Formed on the Retina

Find the radius of a star image formed on the retina of the eye if the aperture diameter (the pupil) at night is 0.70 cm and the length of the eye is 3.0 cm. Assume the wavelength of starlight in the eye is 600 nm. (1 nm = 10 ^{- 9} m)

A) 5.2 *10^-4 m
B) 3.1 *10^-6 m
C) 2.6 *10^-6 m
D) 2.6 *10^-4 m