How must you end an informal letter?
A) Yours sincerely-Charles
B) Yours obediently-Charles
C) No need to write anything
D) None of these

Hint: A casual letter is one that is written in a relaxed tone. If you have a friendly relationship with your formal contacts, you can write an informal letter to them. Depending on the country you're in, there are various methods for composing this type of letter.

Complete answer:
A closing sentence is typically used to indicate that the correspondence has ended and is addressed to the message's recipient. It's the opposite of a salutation.
Let us look at the given options:
A) Yours sincerely-Charles: This is the correct option. When we know the receiver, we use the closing word 'yours sincerely,' according to UK custom. 'Yours sincerely- Charles' is also the most informal approach to end the letter out of the possibilities provided. As a result, option A is right.
B) Yours obediently-Charles: This option is incorrect because it is a formal letter format that is designed to express more respect. This option is inappropriate because we are writing an informal letter.
C) No need to write anything: This option is incorrect because, in order to follow the accepted format, the letter must end with a proper closing phrase.
D) None of these: This option is incorrect because the correct answer is Option A.

Thus, the correct answer is Option (A) i.e, Yours sincerely-Charles.

Note: You might not want to add the words "Love" or even "Affectionately" in a casual letter to someone you're friendly with but not close friends with. "Kind regards" and "As always" are cordial, but not unduly so. Other options include "As always" and "Warm regards." For example, "till next time" would be appropriate