drop down list – What is better: a disabled dropdown or a dropdown with only one choice?

Sometimes, a web application uses a dropdown to present the user with a number of choices. For example:

Choose your size:
    | Small       ▼ |

However, sometimes there is only one available choice.

The designer then has two choices:

  • To make the option the only option in the dropdown.
  • To make the dropdown disabled, with a notice that only the selected option is available.

Which is better?