Topic: Pronoun (সর্বনাম),

Best Answer Explained in Below-:

The correct answer to the sentence "Some people have never known __ it is like to be free" is "D) that." The choice of "that" is essential because it serves as a demonstrative pronoun that introduces a noun clause, allowing the structure of the sentence to flow clearly and logically.

In this context, the phrase "what it is like to be free" conveys a specific experience or state of being. The word "that" effectively connects the subject "Some people" to the experience they have not known, making it clear that the speaker is referring to a particular, tangible concept: the experience of freedom.

Using "what" (Option B) could also seem appropriate but would shift the emphasis toward inquiring about the nature of freedom rather than confirming the absence of personal experience. Options A (which) and C (when) do not fit as they either introduce a restrictive clause or suggest a temporal question, neither of which aligns with the intended meaning. Therefore, "that" is the most suitable choice, providing clarity and coherence to the expression of the lack of knowledge about the experience of freedom.