When calling a customer by phone to address a problem or disappointment, you should describe the problem and apologize, offer an explanation and resolution, and $\_\_\_\_\_\_\_.$

a$.$

follow up with a written message that documents the phone call and promotes goodwill

b$.$

suggest a face$-$to$-$face meeting to resolve any remaining issues

c$.$

provide resale information or promote products and services

d$.$

come to an agreement on a refund or compensation