Explanation: RD (1)- 56; What (interrogative adjective) books (noun) এবং বাকিগুলোতে what interrogative pronoun হিসাবে বসেছে।
-wh-word (who, whose, whom, which, what) + verb- interrogative pronoun
- What+noun, which+noun- interrogative adjective
- When, Where, How, How much, Why- interrogative adverb