$[Co_2(CO)_8]$ displays

• A
  one $Co-Co$ bond,six terminal $CO$ and two bridging $CO$
• B
  one $Co-Co$ bond,four terminal $CO$ and four bridging $CO$
• C
  no $Co-Co$ bond,six terminal $CO$ and two bridging $CO$
• D
  no $Co-Co$ bond,four terminal $CO$ and four bridging $CO$