Experiment and Sample Space

" From a bin of 20 apples, a sample of 4 is chosen. The number of rotten apples in the sample is counted. What is the sample space ? "

The above question seems very simple but I am confused about finding the actual Experiment and the Sample Space involved in this question.

This is what I know :

Experiment : Any activity that leads to an observable outcome.

Sample Space : The set of all possible outcomes of an experiment.

Event : A subset(desired outcomes) of the sample space.

But, I am not sure if the sample space in the given question consists of just 4 elements( a sample) or it is a set of all possible 4-element samples from the 20 apples.

Also, What exactly is the 'Experiment' in the question ? Is it picking ' a sample of 4 apples ' ?

The only thing I am certain about is the Event. Here, the event is ' Counting the number of rotten apples in a sample '.

Could someone please explain to me about the exact 'Experiment' and 'Sample Space' of the given question ?

E.g., $$GGGG, RGGG, RRGG, ...$$