Final answer:
The correct term that best describes someone who treats guests with cordiality and is an excellent at doing so is 'host'.
Step-by-step explanation:
The question asks to identify which term best describes someone who treats guests with cordiality and is an excellent at doing so. The correct answer is a) host. The term "host" refers to a person who receives or entertains guests. An entertainer might perform or engage the guests in some distinctive way, often professionally. A visitor is someone who goes to see someone or a place, often for a short time. A guest is someone who is received and entertained by a host. In the provided sentence, the subject is clearly performing the role of a host.