1991 Geo Tracker Zero Compression in one cylinder

#2 cylinder has zero compression, while other three have 80 PSI compression. Vehicle dies when ever you come to a stop and runs rough (running on three cylinders).

Does this mean piston rings are bad, or possible hole in piston? I tried pouring little amount of oil in bad cylinder and rechecking compression...still zero pressure.

Does this mean enigne needs rebuild...if so can I replace just that piston or all?

Thanks for the help, Gary