The correct answer is (d). Sleeping sickness is a parasitic disease caused by the protozoan Trypanosoma brucei. It is transmitted to humans through the bite of infected tsetse flies. The disease is characterized by fever, headache, and muscle aches. In the later stages, it can cause sleeping disorders, coma, and death.
(a) Vitamin A deficiency is a common problem in developing countries, but it does not cause sleeping sickness.
(b) Calcium deficiency is also a common problem, but it does not cause sleeping sickness.
(c) High blood pressure is a risk factor for many diseases, but it does not cause sleeping sickness.
Sleeping sickness is a serious disease that can be fatal if not treated. There is no vaccine for sleeping sickness, but there are effective treatments available. If you live in an area where sleeping sickness is common, it is important to take precautions to avoid being bitten by tsetse flies. You should also see a doctor if you develop any of the symptoms of sleeping sickness.