The answer is (D): blacklegged tick.
Explanation for each option:
(A) Mosquitoes: Incorrect. Mosquitoes are not vectors for Lyme Disease. They are known to transmit other diseases such as malaria, dengue fever, and Zika virus.
(B) Dog tick: Incorrect. The dog tick, also known as the American dog tick, is not the primary vector for Lyme Disease. It is more commonly associated with transmitting Rocky Mountain spotted fever.
(C) Scabies: Incorrect. Scabies is caused by a mite infestation and is not a vector for Lyme Disease. It is a skin condition resulting from the mite Sarcoptes scabiei.
(D) Blacklegged tick: Correct. The blacklegged tick, also known as the deer tick (Ixodes scapularis), is the primary vector for Lyme Disease in the United States. It transmits the bacterium Borrelia burgdorferi, which causes the disease.
In summary, the blacklegged tick is the primary vector for Lyme Disease in the U.S.