Good manners are essentially​

A) ​thinking of the welfare of another,as expressed through kind,considerate behavior.
B) ​relaxed informality in the workplace.
C) ​rules established by older people who are rather inflexible and stoic.
D) ​traditional rules for behavior passed down over many years.

Good manners involve thinking of others and behaving in a kind and considerate way, therefore option A is the most appropriate choice. Option B, relaxed informality, may be appropriate in some situations, but it is not always the best approach. Option C implies that good manners are rigid and unchanging, which is not necessarily true. Option D is partially correct, but good manners also involve taking into account the needs and feelings of others in addition to following traditional rules.