Final answer:
The mismatched item among the options is 'a. hydatid disease humans are the definitive host,' because in hydatid disease humans are actually intermediate hosts, not definitive hosts.
Step-by-step explanation:
The mismatched item among the given options is a. hydatid disease humans are the definitive host. In the case of hydatid disease (echinococcosis), humans are actually an intermediate host, not the definitive host. The definitive hosts are typically carnivores such as dogs, whereas humans become accidental hosts by ingesting eggs from the environment, leading to the formation of hydatid cysts in organs like the liver and lungs.
Trichinellosis is correctly matched as humans can contract the disease by eating the larvae of the parasite in undercooked meat. Pinworm infestation occurs when humans ingest the eggs of the pinworm. Taenia infestation, where humans are definitive hosts, is also accurately matched because the adult tapeworms live in the human intestine after the ingestion of undercooked meat containing the larvae. Lastly, hookworm infestation is accurate as the parasite enters the host through the skin, typically the feet.