Question

The Mir space station held the record for the longest continuous manned flight in space. Cosmonauts and astronauts from thirteen nations spent time aboard the station. International collaboration became a hallmark of the station.

What is the best way to combine these simple sentences into one compound sentence?
A.
The Mir space station held the record for the longest continuous manned flight in space; cosmonauts and astronauts from thirteen nations spent time aboard the station, and international collaboration became a hallmark of the station.
B.
The Mir space station held the record for the longest continuous manned flight in space cosmonauts and astronauts from thirteen nations spent time aboard the station international collaboration became a hallmark of the station.
C.
The Mir space station held the record for the longest continuous manned flight in space so cosmonauts and astronauts from thirteen nations spent time aboard the station, but international collaboration became a hallmark of the station.
D.
The Mir space station held the record for the longest continuous manned flight in space, but cosmonauts and astronauts from thirteen nations spent time aboard the station and international collaboration became a hallmark of the station.