Pepsi$-$Cola made freshness an important product attribute when it stamped freshness dates on its cans. Prior to doing so$,$ few consumers considered cola freshness an issue. Pepsi is trying to change consumer's attitudes toward Pepsi by

$$ a$.$ Adding a new attribute

b$.$ Changing the perceived importance of a specific attribute

c$.$ Providing stimulus generalization

d$.$ Reducing perceived risk

e$.$ Changing beliefs about the extent to which a brand has a specific attribute