In standard twelve-bar blues, which chords are primarily used?

In standard twelve-bar blues, the primary chords used are the I, IV, and V chords. This specific progression forms the foundation of many blues songs and reflects the genre's musical structure.

In this context, the I chord represents the tonic, establishing the home key of the piece. The IV chord, which is a perfect fourth above the tonic, introduces a sense of movement and tension as it transitions to the V chord, the dominant, which creates an even greater sense of tension that resolves back to the I chord.

This cycle of I, IV, and V in a twelve-bar format typically consists of three lines of four measures each, where each line often employs these chords in various sequences. This chord progression is essential to the blues genre, contributing to its characteristic sound and feel.

The other options present different chord progressions that do not align with the traditional twelve-bar blues form, which is why they are less appropriate in this context.