Concept:Yellow fever is a viral disease transmitted by a mosquito vector.Explanation:The main vector for yellow fever is the Aedes mosquito, especially Aedes aegypti.It spreads the yellow fever virus when it bites an infected human or monkey and then bites a healthy person.Other mosquitoes listed transmit different diseases: Anopheles transmits malaria, tsetse fly transmits sleeping sickness, and blackfly transmits river blindness.Answer:A. Aedes mosquito