Answer:
A). Confident
C). Polite
E). Serious
F). Unemotional
Explanation:
A formal letter or email, as the name suggests employed for formal purposes like business situations or to address an issue to an authority. Such letters or e-mail employ a highly formal and sophisticated tone not only to ensure the efficacy of the intended message but also to give a positive impression on the recipient(employer, authority, etc.).
As per the question, the kind of words that one must employ 'confident, polite, serious and unemotional' words like these would assist to invoke a formal, intricate, and sophisticated tone to the letter or e-mail. Thus, <u>options A, C, E, and F</u> are the answers.