Which of the Following Requisites Is Absolutely Necessary in Order

Multiple Choice

Which of the following requisites is absolutely necessary in order to train an animal to "sniff out" tumors or other health problems on a patient?

A) The animal must be bonded with the patient.
B) The animal must be able to discriminate between healthy and unhealthy samples.
C) The patient must have a clinically significant symptom.
D) The patient must be aware of the onset of symptoms or discomfort.