5) delete it from your code. You do have source control, so you will be able to recover the code later. If you want to leave evidence, add a comment:

  -- Removed Foo handling in revision ... because of ...

That should be rare, though.

For temporary disabling, I tend to do:

   const disableFooForDebugging = true
   if( disableFooForDebugging)

That makes it easier to recognize and correct accidental checkins.