What is the best way to combine the following sentences into one compound sentence?
(14) The Smithsonian is a large complex. (15) It has 19 museums, 9 research centers, multiple galleries, and a zoological park.
A.
The Smithsonian is a large complex but has 19 museums, 9 research centers, multiple galleries, and a zoological park.
B.
The Smithsonian is a large complex with 19 museums, 9 research centers, multiple galleries, and a zoological park.
C.
The Smithsonian is a large complex and has 19 museums, 9 research centers, multiple galleries, and a zoological park.
D.
The Smithsonian is a large complex, and it has 19 museums, 9 research centers, multiple galleries, and a zoological park.