Most Primates Rely More on Visual Stimuli and Less on Olfactory

Most primates rely more on visual stimuli and less on olfactory stimuli than do other mammals. Which of the following is one line of evidence for this?

A) Primates have more complex eyes than do other mammals.
B) Primate olfactory apparatuses are highly specialized, especially in diurnal primates.
C) Primates have more olfactory nerves than do other mammals.
D) The primate visual sense is highly developed while the olfactory apparatus is reduced, especially in diurnal primates.