Rodents can distinguish between many different types of odours. The basis for odour discrimination is that-
(A) they have a small number of odorant receptors that bind to many different odorant molecules
(B) the mechanoreceptors in the nasal cavity are activated by different odorant molecules found in the air
passing through the nostrils
(C) the part of the brain that processes the sense of smell has many different receptors for odorant molecules
(D) a large number of different chemoreceptors are present in the nasal cavity that binds a variety of odorant
molecules