If there is no translation for page, how to display language selector

I have a site in two different languages, let's say English and Swedish. There's a language selector in the top right corner which displays these languages and allows you to switch between these.

However, some pages only have a version in one language. What should happen to the language selector in this case?

  1. Hide the language selector if there is no translation
  2. Show the language selector in a disabled state
  3. Show the language selector, but if the user clicks it, they will be redirected to the front page (which is translated)
  4. Show the language selector, but if the user clicks it, traverse up the site tree structure and redirect the user to the first translated page