**Core Concept**
Pigs are considered reservoir hosts for several zoonotic parasites, which can be transmitted to humans through various routes. The Taenia species and Trichinella spiralis are among the parasites that use pigs as their intermediate host.

**Why the Correct Answer is Right**
Trichinella spiralis is a parasitic roundworm that causes trichinosis in humans. Pigs are the primary reservoir host for T. spiralis, and the parasite's lifecycle involves the ingestion of contaminated meat, which leads to the encystation of larvae in the pig's muscles. When humans consume undercooked or raw infected pork, they become infected with T. spiralis. The parasite's ability to form cysts in the muscle tissue of pigs makes them an ideal intermediate host.

**Why Each Wrong Option is Incorrect**
* **Option A:** T. solium (pork tapeworm) uses pigs as an accidental host, not a reservoir host. Pigs can become infected with T. solium through the ingestion of contaminated feces containing T. solium eggs.
* **Option B:** T. saginata (beef tapeworm) uses cattle as its intermediate host, not pigs.
* **Option D:** Ancylostoma species, such as Ancylostoma duodenale and Necator americanus, are hookworms that infect humans through skin contact with contaminated soil and are not typically associated with pigs.

**Clinical Pearl / High-Yield Fact**
Pigs can serve as reservoir hosts for various zoonotic parasites, highlighting the importance of proper meat handling, cooking, and hygiene practices to prevent transmission of these parasites to humans.

**Correct Answer:** C. Trichinella spiralis