The monoamine serotonin is synthesized mainly by enterochromaffin cells in the intestine. A mouse was treated with broad range of antibiotics for a week. After a week, both the diversity of gut microbiota and serum serotonin levels was reduced. In another independent study, a co-culture of Lactobacillus and enterochromaffin cells induced serotonin synthesis. Based on these observations, the reason for decreased serum serotonin in antibiotic treated mouse would most likely be
a. Antibiotics inhibit serotonin synthesis
b. Gut micro biota play an important role in serotonin biosynthesis
c. Antibiotics make the mouse depressed and hence reduce the levels of serotonin
d. Antibiotics degrade serum serotonin