a) tsetse fly
Tsetse fly (Glossina palpalis)
I would choose A.
Human African trypanosomiasis, sleeping sickness,[1] african lethargy,[1] or Congo Trypanosomiasis[1] is a parasitic disease of humans and animals, caused by protozoa of the species Trypanosoma brucei and transmitted by the tsetse fly.[2] The disease is endemic in parts of sub-Saharan Africa, covering around 36 countries and 60 million people. An estimated 50,000 to 70,000 people are currently infected, a number that has fallen somewhat in recent years.[3] The number of reported cases was below 10,000 in 2009, the first time in 50 years.[4] Many cases are believed to go unreported. About 48,000 people died in 2008.[5] Four major epidemics have occurred in recent history: one from 1896 to 1906 primarily in Uganda and the Congo Basin, two epidemics in the 1920s and 1970s in several African countries, and a recent 2008 epidemic in Uganda.[6]