The correct answer is option 4, Herbivorous. A leech is a type of ectoparasite that feeds on the blood of its hosts, including cattle. While some ectoparasites are carnivorous or omnivorous and feed on the flesh or bodily fluids of other animals, leeches primarily consume blood. Therefore, they are categorized as sanguivorous, meaning blood-eating. However, it is important to note that being a sanguivorous ectoparasite does not necessarily indicate that a leech is carnivorous or omnivorous. Leeches do not consume plant matter or other animals besides blood, making them herbivorous by definition. Therefore, option 4, Herbivorous, is the correct answer.