Answer:
b. etiology
Step-by-step explanation:
Etiology -
Etiology refers to the cause or reason for a particular disease , is termed as etiology.
It is the science which deal with the cause of any disorder or disease.
As we visit doctor , the doctor tries to find the etiology of the disease ,with the help of some basic tests and the information the patient patient provides.
Hence, from the given scenario of the question,
Dr. Littlefox studies etiology of the disorder.