একটি বইয়ে ৪০০ পৃষ্ঠা এবং আরেকটি বইয়ে ৩৫০ পৃষ্ঠা আছে। কোন বইটি বেশি পুরু? 
To solve this problem, let's analyze it step-by-step:

Step-1: There are two books, first one has 400 pages and the second one has 350 pages.

Step-2: Considering all pages are identically thick, we can say that the more pages makes the book more thicker.

Step-3: Here the first book has more pages than then the second one. That means the first book is more thicker than the second one.

Step-5: So, the answer is “First book (400 pages)” which is actually “Option 2”

#Answer: [Option 2]
