The Pupil of a Cat's Eye Narrows to a Slit $\lambda$

Multiple Choice

The pupil of a cat's eye narrows to a slit width of 0.5 mm in daylight.What is the angular resolution of the cat's eye in daylight ( $\lambda$ = 500 nm) ?

A) 0.01 rads
B) 10 ^{- 5} rads
C) 10 ^{- 3} rads
D) 10 ^{- 4} rads
E) 0.1 rads