Roy Harold Purchased a New Washer/dryer for His Apartment

Roy Harold purchased a new washer/dryer for his apartment.Shortly after the appliances had been installed,a store representative called Harold and asked if he were satisfied with the washer/dryer and how they were installed.The store representative also asked Harold to call if he had any further needs for appliances.According to Kotler and Armstrong,this is an example of which relationship level?

A) Reactive relationship
B) Basic transactional relationship
C) Accountable relationship
D) Proactive relationship
E) Partnership