Concept:Ecto-parasites live on the outside of the host's body, so they are controlled by external chemical treatment.
Explanation:Dipping means immersing the animal in a chemical solution, which kills or removes ecto-parasites such as ticks, lice, and mites on the skin surface.
Antibodies and antibiotics work inside the body, so they cannot effectively treat parasites living on the surface.
Deworming targets internal worms found in the digestive tract, not external parasites.
Therefore, the most suitable method is dipping the host.
Answer:C. dipping of host