I want an exhaustive answer, not a summarized one

Let’s say, a text deals with Topic1,Topic2,Topic3 and Topic4 .

I offer the string to a llm and write:

Which topics is this text dealing with?

The result is either Topic1 or Topic1,Topic2 or … but never Topic1,Topic2,Topic3 and Topic4.

How can I create or modify a llm to output Topic1,Topic2,Topic3 and Topic4 whereas Topic is arbitrary.

The point is, I want an exhaustive answer, not a summarized one.