Final answer:
Ray Wylie Hubbard is the Austin honky-tonk musician who says a lot of life happens at Whataburger booths.
Step-by-step explanation:
The Austin honky-tonk musician who claims that, "man, a lot of life happens in the booths at Whataburger," is D) Ray Wylie Hubbard. Ray Wylie Hubbard is well-known for his storytelling in songs, which often reflect his Texas roots and the lifestyle around honky-tonks and local culture.
Whataburger, a popular Texas fast-food chain, is frequented by many locals, including musicians, and is the place where Hubbard has observed much of the everyday life and human interactions that inspire his music.