"The good boys are eating apples."
Translation:Dobrzy chłopcy jedzą jabłka.
Chłopak is an unusual noun as it has two plural forms in nominative (but one word for each other case), chłopacy and chłopaki. Other masculine personal nouns can behave similarly but usually one of the two words is depreciative towards the person (the non-masculine-personal variant), in case of chłopak none of them show any negative attitude.
Chłopacy demands that you use ci (as it's masculine personal plural).
Chłopaki demands that you use te (as it's non-masculine-personal).
Now I see that the best translation shows "dobrzy chłopcy", this is from another noun, chłopiec. But its meaning is different to chłopak, chłopiec is a child up to early teenhood, while chłopak is usually older.
So we have three correct options "dobrzy chłopacy", "dobrzy chłopcy" and "dobre chłopaki".
Almost: it's technically this/these.
But then, given what "the" actually means, given that "the boys" mean that they have been mentioned already, it's really almost the same as "these boys". That's why we accept translating "The boys" as "Ci chłopcy". It will never be the main, suggested answer (so you can ignore it and go with the literal translation), but it's accepted.