Refer to the Figure

Refer to the figure. Identify the structures labeled 1, 2, 3, and 4 in the figure, starting with 1 and ending with 4.

A) Olfactory cilia of olfactory receptor neurons, axons of olfactory receptor neurons, glomeruli, olfactory bulb
B) Axons of olfactory receptor neurons, olfactory cilia of olfactory receptor neurons, olfactory bulb, glomeruli
C) Olfactory cilia of olfactory receptor neurons, ligands of olfactory receptor neurons, cilia of glomeruli, olfactory bulb
D) Glomeruli, axons of olfactory receptor neurons, olfactory cilia of olfactory receptor neurons, olfactory epithelium
E) Olfactory microvilli of olfactory receptor neurons, axons of olfactory receptor neurons, glomeruli, olfactory epithelium