Veterinary technician the person who helps in assisting the veterinarian in diagnosing and treating any animals in the hospital. The responsibility of veterinary technician is to perform medical tests on animals like taking blood, urine or stool samples, taking X- rays, giving medication to the animals, perform dental procedures, giving anesthesia to animals during a medical exam, etc.
A veterinary technician requires special training and a license which is not given to Veterinary assistants. So the correct answer is A.
