What four chords are commonly used in rock music?

In rock music, there are four chords that are commonly used and often referred to as the "power chords" or the "basic rock chords." They are:

1. G major (G)

2. C major (C)

3. D major (D)

4. E minor (Em)

These four chords form the foundation of many rock songs and are frequently used in various progressions and combinations. They provide the basic harmonic structure for many popular rock riffs, power ballads, and classic rock anthems.