Nike launched a new series of advertisements with Colin Kaepernick as the face of the brand. Allen and his friends used to wear Nike compression sleeves when they played AAA varsity football. This year, to avoid controversy, they decided to buy no$-$name sleeves. Nike is part of which group that influences Allen's buying decisions?

a$.$ Primary membership group

b$.$ Secondary membership group

c$.$ Dissociative group

d$.$ Aspirational reference group