The correct answer is option 3, the Tsetse fly. The sleeping sickness disease, also known as African trypanosomiasis, is caused by a parasite called Trypanosoma which is transmitted to humans through the bite of infected Tsetse flies. Tsetse flies are found in sub-Saharan Africa and are primarily active during the day. They feed on the blood of animals and humans, and during the feeding process, they pass on the parasite, leading to the transmission of the disease. It is important to note that the other options listed, such as bedbugs, lice, and sand flies, do not play a role in the transmission of sleeping sickness. Therefore, the correct vector responsible for spreading this disease is the Tsetse fly.