Sentence Correction

Although it is a federal body, nevertheless the Federal Bureau of Investigation does not enforce law in the United States, this responsibility belonging to the state and local authorities.

A. Although it is a federal body, nevertheless the Federal Bureau of Investigation does not enforce law in the United States, this responsibility belonging
B. Although the Federal Bureau of Investigation is a federal body, nevertheless it does not enforce law in the United States, this responsibility belonging
C. The Federal Bureau of Investigation, although a federal body, do not enforce law in the United States, this being a responsibility that belongs
D. The Federal Bureau of Investigation, although it is a federal body, do not enforce law in the United States, this responsibility belonging
E. The Federal Bureau of Investigation, although it is a federal body, does not enforce law in the United States, this responsibility belonging

OA: E
What's wrong with options B and D? Can any experts help?

ardz24 wrote:What's wrong with options B and D?

B: Although the Federal Bureau of Investigation is a federal body, nevertheless it does not enforce law.
Here, although and nevertheless are redundant.
Eliminate B.

D: The Federal Bureau of Investigation...do not enforce law in the United States.
Here, do not enforce (plural) does not agree with the Federal Bureau of Investigation (singular).
Eliminate D.