The option that is not a type of user interface is: Application Programming Interface (API) (or more generally, anything like “efficiency- based” that describes a quality rather than an interface style).

What counts as a user interface?

Common types of user interfaces include:

  • Command-driven / command-line interface (CLI).
  • Menu-driven / menu-based interface.
  • Graphical user interface (GUI, including WIMP: windows, icons, menus, pointer).
  • Direct manipulation / iconic interfaces.
  • Form-based interfaces.

These are all ways a human directly interacts with software through screens, commands, menus, or forms.

What is not a user interface?

  • An Application Programming Interface (API) is a set of rules and protocols that lets software components talk to each other, not a human-facing interaction layer.
  • Terms like “efficiency-based” describe a quality of a UI (how fast or effective it is) rather than an actual interface type.

So in typical MCQs such as:

Which of the following is not a type of user interface?
A) Command-driven
B) Application programming interface (API)
C) Menu-driven
D) Graphical user interface

The correct answer is B) Application programming interface (API).

Information gathered from public forums or data available on the internet and portrayed here.