Oftentimes English speakers will use foreign words to express their goodbyes.

Which ones are acceptable? A: It is OK to ask young people about their age. B: Never ask a lady her age. C: Ask how much a person pays for the new phone. D: Show your concern by saying "I hope you will recover soon". E: Drop in a foreigner's home without previous appointment. F: Small talks with the host before your leaving his or her home are preferred to abrupt goodbyes.