You're given a sentence and your task is to classify whether the sentence is acceptable or not. Any sentence which is grammatically correct, has a naturalistic text, is written by a native speaker and which minimizes superfluous content is acceptable, otherwise unacceptable. If the sentence is acceptable then write "acceptable", otherwise "unacceptable".

Every student answered any question.
unacceptable

Whether this is feasible hasn't yet been determined.
acceptable

Selina touched the horse on the back.

acceptable