Which one of these methods is realistic

The following technologies:

Magnetic sails
Mini-magnetospheric plasma propulsion
Nuclear pulse propulsion (Orion drive)
Gas core reactor rocket
Antimatter catalyzed nuclear pulse propulsion
Nuclear salt-water rocket
Beam-powered propulsion
Fission sail
Fission-fragment rocket
Nuclear photonic rocket

The following technologies are significantly beyond current engineering:

Fusion rocket
Bussard ramjet
Antimatter rocket
Redshift rocket

Go into as much detail as you want, even down to chemistry, physics, and engineering.

all of above and below

All of them are possible, but the ones possible are the Antimatter, Magnetic
Sail, and Nuclear Pulse (my favorite)
Nuclear Pulse can theoretically go 5%
the speed of light, which can get us
to Proxima Centauri (closest star to sun)
in 85 years, which is relatively awesome
seeing as though it is 4.37 light years away
from the sun.

I would say magnetic sails, however you really need to provide a definition of each one please. Awaiting further details.

alll of them!!