Please, don’t laugh . . . . . . those beggars.

The correct answer is C: at

First, let's define the preposition "at" in this context. "At" is used to indicate the direction of an action or feeling towards a specific person or thing.

The sentence "Please, don't laugh . . . . . . those beggars" implies a request to refrain from a disrespectful action directed towards the beggars. Laughing "at" someone implies mockery or ridicule, which is the negative action the sentence seeks to prevent.

Let's look at why the other options are incorrect:

A: for - "Laugh for" implies laughing because of something, not at someone. This doesn't fit the context of the sentence.

B: against - "Laugh against" isn't a standard English expression. It doesn't make logical sense in this context.

D: from - "Laugh from" suggests the source of laughter, not the target. This also doesn't fit the meaning of the sentence.

Therefore, only "at" accurately conveys the intended meaning of directing the action of laughter towards the beggars, highlighting the negative connotation of mocking them.