The principal vector of dengue virus-: (A) Anopheles culicifacies, (B) Aedes aegypti, (C) Anopheles stephensi, (D) Culex molestus
Answer is B. The principal vector of dengue is the mosquito Aedes aegypti, which breeds in standing water; collections of water in containers, water based air coolers & tyre drumps are a god environment for the vector in large cities. Reference: Harrison20th edition pg 879