"You do not eat an apple."
Translation:Tu nu mănânci un măr.
Yes. "You" can refer to either one person or many, and this sentence doesn't clarify which.
Choice 2- the milk doesn't eat the Apple. Choice 3- you don't child an apple. Hahahahaha! Funny right? No? Okay.
I don't know what niciun is but sounds unnecessary here. Is this sentence correct without "niciun"?