Final answer:
The core group in a grunge band consisted of guitar, bass, and drums. Grunge music differed from other rock genres in heavier sound through detuned guitars, substantial lyrical content, and the casual style of the musicians.
Step-by-step explanation:
The core group in a grunge band consisted of A. Guitar, bass, and drums. Grunge music, especially from the Seattle area, was distinct from other rock genres of the time. It had a heavier sound partly due to many guitarists detuning their guitars. The lyrical content of grunge bands was typically more politically charged or reflective of social issues, such as mental illness and drug dependency, which contrasted the party-centric lyrics of many LA-based bands. Additionally, the style of Seattle's grunge musicians was markedly understated with a preference for casual attire over the glamorous looks of the hair metal bands.