Amin finds that every time he goes to select athletic shoes, he always buys the same brand. In fact, he doesn't even remember trying on any of the other competitive brands even though some of these brands have attractive styles and prices. Amin's purchase decision process has become one of less and less effort. Amin's decision process in an example of

$$ a$.$ cognitive dissonance

b$.$ ineptness

c$.$ brand loyalty

d$.$ inertia