The correct answer is Option 1: Trypanosoma. Sleeping sickness, also known as African trypanosomiasis, is a disease caused by the protozoan parasite Trypanosoma. This parasite is transmitted to humans through the bite of infected tsetse flies, which are found in sub-Saharan Africa.
Option 2: Leishmania is incorrect. Leishmania is the causative agent for a different parasitic disease called leishmaniasis, which is transmitted through the bite of infected sandflies.
Option 3: Plasmodium is also incorrect. Plasmodium is the parasite that causes malaria, a mosquito-borne disease.
Option 4: Paramecium is a free-living ciliated protozoan and is not responsible for causing any diseases in humans.
Therefore, the correct cause for sleeping sickness is Trypanosoma, and it is important to take preventive measures to avoid being bitten by tsetse flies in areas where the disease is endemic.