The bare minimum?
With inline operations. Takes a lot of vertical space, but operation links are likely very near the pointer (?)
No operations, author name links to profile if possible (not useful for comments when anon. commenting is on).
Similar to how tables like this are shown on pages. Using :hover visibility for the operation links to minimize visual (repetitive) noise.
Same as D but with author and different placement of show all link (following the flow of the operation links).