TOEFL® question: ...at the site of a fort established by the Northwest Mounted

[Petra]

... at the site of a fort established by the Northwest Mounted Police, Calgary is now one of Canada’s fastest growing cities.

(A) Built
(B) It is built
(C) To build
(D) Having built.

My answer is : D , having built.

Is this the right choice?

In the key it was given as A

what would be the reason to chose A?

Thanks Torsten for your help :D

Petra

TOEFL listening discussions: Why are these young men in conversation?

[Latha]

Thanks for expalnation

[hien pham]

Calgalry was built, not having built
So , Built (A) that is correct sentence
regards,
Hien pham

[Guest]

D is the correct answer and answer A doesn't make sense...

[hfk]

Calgary, built at the site of a fort established by the
Northwest Mounted Police, is now one
of Canada’s fastest growing cities.