"Do you laugh at the fat boy?"

Translation: Voi râdeți de băiatul gras?

[tatianandreeva]

Is 'de' or 'la' the correct preposition here? There was another example where both were shown as acceptable.

[dmivapi]

Agree. I saw the sentence where la was acceptable. I reported Voi râdeți la băiatul gras as acceptable. Not sure if I am right