Select the Sequence of Events for the Olfactory Pathway

Multiple Choice

Select the sequence of events for the olfactory pathway
1) a second messenger opens cation channels (Na⁺ and Ca⁺²)
2) depolarization of olfactory receptor cells occurs
3) odorant binds to olfactory receptor protein
4) G protein activates cyclic adenosine monophosphate

A) 1,2,3,4
B) 4,2,1,3
C) 3,4,1,2
D) 2,1,4,3
E) 3,1,2,4