It's the Genesis version of MKII since the characters' names are underneath the health bar. The SNES and arcade versions have the characters' names inside the health bar.

I have Mortal Kombat 2 for Sega Genesis and the names are inside of the health bar. SNES is the one that has the names outside of the health bars. If you don't believe me look up MK2 Sega Genesis gameplay on Youtube. Unless I have had an abnormal version of the game for about 20 years(Which is extremely unlikely) I can guarantee the character's names will be located inside of the health bar. Then look up MK2 SNES gameplay, I am sure the names are right below the health bar, not inside of it.

SNES Mortal Kombat II had the better gameplay but I always liked the Genesis music better do to being more dark and mysterious fitting the game so well.