Would You Expect an Individual with Giardiasis Who Has Diarrhea

Would you expect an individual with giardiasis who has diarrhea to be more likely to transmit the disease than an individual with giardiasis who does NOT have diarrhea? Why or why not?

A) No-this illness is spread by respiratory droplets, so diarrhea as a symptom shouldn't matter for transmission of the disease.
B) No-this illness is spread by sexual contact, so diarrhea as a symptom shouldn't matter for transmission of the disease.
C) Yes-this illness is spread by the fecal-oral route, so presence of diarrhea as a symptom should dramatically increase the possibility of transmission of infection.
D) Yes-this illness is spread by insects that feed on contaminated fecal matter, becoming infected themselves. The disease is spread to new individuals when these infected insects bite a susceptible person, transmitting the cysts of the protozoan. As such, diarrhea as a symptom would increase the risk of transmission through biting insects to new individuals.