____________ types are mutually exclusive in the sense that a user agent can only support one media type when rendering a document.

tv
tty
media
audio

The correct answer is B. tty.

A tty (teletypewriter) is a text-only terminal device that is used to interact with a computer. It is a character-based device that does not support graphics or multimedia. A user agent can only support one media type when rendering a document, and a tty is a text-only media type. Therefore, a user agent can only support a tty when rendering a document.

The other options are incorrect because they are not mutually exclusive media types. A user agent can support multiple media types when rendering a document.

  • A. tv is a television media type. A user agent can support multiple television media types when rendering a document.
  • C. media is a generic media type. A user agent can support multiple media types when rendering a document.
  • D. audio is an audio media type. A user agent can support multiple audio media types when rendering a document.