Options are a custom color, foreground color or background color.
So that after you execute it once, it remembers the settings and you can just rerun plug-in (with Ctrl+F and execute the same thing again).
This was to address the problem mentioned in this topic -> Change default for Colorize? Plug-in Menu Location:
Just run it, the options are a custom select color. and option to choose to use that color or foreground or background color. pretty much self-explanatory.