For which kind of letter would the following be appropriate:
I request that you correct our notice to reflect the actual value…
This question has multiple correct options.

The given sentence would be appropriate for a proper letter because it talks about some notice and value which most likely refers to a numerical value representing money. Now official letters may be of the many types, one in all them could be a letter. As this sentence refers to someone (I request ‘you’…) Therefore, it can be a private missive. It talks about some corrections in a very bill sent via notice. Thus, option a “formal” and option d “personal-business” are both correct. This line would fit either of those.

Option b “informal” is wrong as this can be not something, we write to a lover or loved one. Option c is correct .

Note: this may be anesthetise missive too because it talks a couple of correction in value amount on a notice.