When to store array vs store new boolean fields

Give this enum:

["A", "B", "C"]

I need to store unique combinations of this enum in my collection. Each item cannot repeat itself.

So I can store it as a field in the collection where the type of this field is “array”, or I can have 3 fields, “A”, “B”, and “C”, where the type are booleans.

For the sake of speed and performance, which design is best? Under what circumstances should I choose one over the other?

In my collection, there are many enums of this type that it needs to store.