The knowledge gap differs from the standards gap in that the standards gap pertains to the difference between

a$.$ actual services provided to customers and services that a firm's promotion program promises.

b$.$ a firm's perceptions of customers' expectations and the service standards it sets.

c$.$ a firm's service standards and the actual service it provides to customers.

d$.$ customers' expectations and a firm's perception of those expectations.

e$.$ customers' expectations and service standards set by a firm.