Fill in the blank with the most appropriate word.
"Please be quiet." I asked them __________ quiet.
The two ways of relating what a person has said are 1)direct and 2)indirect (reported).
In the direct speech, the exact words of the original speaker are repeated.
In the indirect speech (reported speech), the exact meaning of what the speaker told is expressed but not necessarily in the speaker’s exact words.
Option C is correct as the speaker of the indirect speech requests the listeners to be quiet.
Options A, B, and D are wrong as the preposition 'to' is not used, the given speech is not negative, and 'are' cannot be used respectively.
The correct answer is C)to be.