Change the voice: They have eaten all the apples."

All the apples have eaten by them.

All the apples have been eaten by them.

All the apples were eaten by them.

None of these

All the apples have been eaten by them.

In passive voice, the object ("all the apples") becomes the subject and the tense remains present perfect.

Structure: has/have + been + past participle → have been eaten.