In the quoted statement above, the best answer that describes the statement is letter D. befitting a son or daughter. It is because the term filial, it means that it is pertaining to a son or daughter. So meaning, the sentence is pertaining to the son or daughter of the person who is states the sentence above.
The word "filial" is an adjective that describes something that is related to a son or a daughter. The word comes from the Latin. In this case, the phrase describes how the observers were extremely impressed by a particular behaviour that was admirable and wonderful. The observers believe that this behaviour is particularly desirable in a son or daughter.
