Spelling selection — Choose the correctly spelled formal letter closing and adverb: identify the standard dictionary form among the options for professional correspondence.

Given data

• Common letter adverbs/closings presented with one correct spelling.
• Options: Faithfuly; Sincerely; Truely; Affectionatly

Concept/Approach
Identify the correctly spelled adverb used in closings: "Sincerely" is the standard form.

Step-by-step reasoning
Sincerely — correct spelling (often used in "Sincerely yours").Faithfuly — incorrect; correct is "Faithfully" with "ll".Truely — incorrect; correct is "Truly" (drops the "e").Affectionatly — incorrect; correct is "Affectionately" with "ate-ly".

Verification/Alternative
Business writing guides list "Sincerely" as a standard complimentary close.

Common pitfalls
Adding or omitting letters in adverbial endings.

Final Answer
Correct choice: Sincerely.