Respuesta :
d. friendly and respectful because it is a friendly letter, you don't want to be sarcastic which could come off as rude, and you don't want it to be formal either
A friendly letter is a type of letter used to invite, thank, or just tell something to a person to whom we are familiar with. Although the content depends upon the purpose behind the letter, it is usually written in a friendly, familiar tone, rather than a formal one. Therefore, the tone of a friendly letter should be:
D) friendly and respectful.