Final answer:
Schistosomiasis is the disease caused by a helminth, which is a type of multicellular parasitic worm, and occurs when people contact contaminated fresh water.
Step-by-step explanation:
The disease among the options given that is caused by a helminth is c) Schistosomiasis. Helminths are multicellular parasitic worms that can cause various diseases. Schistosomiasis, also known as snail fever or bilharzia, is caused by parasitic flatworms called schistosomes. People become infected when they come into contact with fresh water that has been contaminated with the larval forms of the parasite, which are released from infected freshwater snails. The larvae then penetrate the skin of humans and develop into adult worms inside the body, leading to a range of health issues.