The $\frac{80}{20}$ Rule, as a rule of thumb, states that

A$.20$ percent of users account for $80$ percent of sales

B$.80$ percent of marketing expenditures result in $20$ percent of sales

C$.20$ percent of marketing expenditures result in $20$ percent of sales

D$.80$ percent of users disregard $20$ percent of marketing efforts

E$.80$ percent of users account for $20$ percent of sales