In naturalistic observation, the practice of dichotomous recording of whether a behaviour occurs or not constitutes:

Recording merely whether a behaviour occurs or not within an interval is one/zero sampling.

Cluster sampling is a technique for selecting participants in groups, not for coding behaviour.

Time-interval sampling notes behaviour within set periods but does not by itself imply a yes or no code.

Continuous real-time sampling records every occurrence and its duration, not a simple dichotomy.

One/zero sampling scores each interval as behaviour present or absent, ignoring frequency within it.

It is simple to use but can overestimate the true rate of a behaviour.