The ability of the olfactory system to adapt to a particular odor may involve

A) sensitivity of the olfactory cortex.
B) an increase in the sensitivity at the receptor sites.
C) neurons from the medial olfactory area stimulating mitral cells and tufted cells.
D) the intermediate olfactory area sending inhibiting impulses to the olfactory bulb.
E) molecules that do not bind to receptors anymore.