Which waveform is typically characterized by sharp transitions between states?

The square wave is characterized by its sharp transitions between high and low states, making it easily identifiable. This waveform alternates between two levels with instantaneous changes, resulting in a signal that jumps directly from one state to another without gradual transitions. This sharpness provides a clear distinction in its timing and frequency, which is why square waves are commonly used in digital circuits and systems where precise on-off states are required, such as in timing applications or pulse modulation.

In contrast, sine waves exhibit smooth and continuous oscillations, gradually transitioning through values rather than making sharp changes. Triangle waves have linear rises and falls, creating a softer transition than square waves. The term "transmission wave" is not typically used to describe a specific type of waveform, and may refer to various types of waves used in different contexts. Therefore, the square wave is the correct choice due to its distinctive sharp and instantaneous transitions between states.