The correct option is B theism
Option B: 'Theism' is a belief in the existence of gods.
Option A: Pragmatism is a practical approach to beliefs.
Option C: Action is a process of doing something.
Option D: Liberation is a freedom from thoughts or behaviour.
From these words, 'theism' is most suitable here, as the argument is: that pure spiritual atheism is a superior form of theism.
There are many theorists who believe that atheism in its most spiritual form acknowledges the existence of a higher being, which is theism.
Hence option B is correct.
The other words do not seem relevant to the given sentence, hence A, C, D are incorrect.