Which closing phrase would be least suitable for a strongly formal complaint letter?

Which closing phrase would be least suitable for a strongly formal complaint letter?

• A. Yours sincerely
• B. Best regards
• C. Kind regards
• D. Yours faithfully

Answer: (C)

In formal writing, the closing should match the level of formality and the professional relationship you’re addressing. For a strongly formal complaint letter, you want a sign-off that reinforces seriousness and professionalism. The standard options are the ones that are clearly formal: for a named recipient, that ends with a phrase like “Yours sincerely”; if you don’t know the name, you’d use “Yours faithfully.” A closing such as “Best regards” is polite and acceptable in many business contexts, but it’s still somewhat less formal. “Kind regards” introduces a warmer, more personal tone, which can undermine the formal, assertive stance you’re aiming for in a strong complaint. That warmer feel is why it’s the least suitable choice in this situation.

In formal writing, the closing should match the level of formality and the professional relationship you’re addressing. For a strongly formal complaint letter, you want a sign-off that reinforces seriousness and professionalism. The standard options are the ones that are clearly formal: for a named recipient, that ends with a phrase like “Yours sincerely”; if you don’t know the name, you’d use “Yours faithfully.” A closing such as “Best regards” is polite and acceptable in many business contexts, but it’s still somewhat less formal. “Kind regards” introduces a warmer, more personal tone, which can undermine the formal, assertive stance you’re aiming for in a strong complaint. That warmer feel is why it’s the least suitable choice in this situation.