complexity theory – How to know if language is in comp or np?

I’m new to the site.

I had a test a few days ago and failed it, I had a question I did not understand.

This is the question:

Let’s look at the FALSE language: Collect all the verses P in the form of CNF so that any placement on the variables P will not satisfy P. We will mark the number of variables in N and the number of verses in M.
Determine which of the following statements is correct:

  1. The language is in P. You can build an algorithm running in time O (max{N^5, M*N}^2)
  2. The language is in NP.
  3. The language is in CONP.

How do I know what the correct answer to the question is? How can I tell if the FALSE language belongs to np or conp I do not understand.