Which of the following anthelmintics targets cestodes?

Praziquantel is specifically designed to target cestodes, which are flatworms commonly known as tapeworms. This anthelmintic functions by causing severe damage to the parasite's tegument (outer protective covering), leading to paralysis and eventual death of the cestode. Praziquantel is particularly effective against various species of tapeworms, including those that infect humans and animals, making it a key agent in the treatment of infections caused by these parasites.

The other substances—levamisole, mebendazole, and ivermectin—are effective against different types of helminths. Levamisole primarily targets nematodes (roundworms) by acting as a neuromuscular blocker. Mebendazole is also geared towards nematodes and works by inhibiting microtubule formation, while ivermectin is most effective against certain parasitic arthropods and nematodes. Thus, praziquantel stands out as the correct choice as it specifically addresses cestode infections.