Which of the gestalt principles states that we tend to perceive objects in groups?

The law of perceptual grouping is the Gestalt principle which states we tend to perceive objects in groups. Gestalt theory maintains that we group objects in several different ways: according to similarity, proximity (when they are near each other), law of common fate, law of continuity (we prefer perceptions of connected and continuous figures to disconnected perceptions ... examples would be a movie or a song), and the law of pragnanz (we look for the simplest way to see things ... however it requires the least thinking).