Reference groups are extremely important to marketers in three ways: $(1)$ They serve as information sources and influence perceptions; $(2)$ they affect an individual's aspiration levels; and $(3)$

a$.$ their norms either constrain or stimulate consumer behavior

b$.$ their connection to consumers is selective

c$.$ they only stimulate high$-$end purchases by upper social classes

d$.$ they can have only negative implications directly influence consumer behavior.