Institution: Directorate of Primary Education - DPE Exam: Primary Exam Question Solution 24-05-2019
Topic: Fill in the Blank, Subject: English Grammar (ইংরেজি গ্রামার)

Best Answer Explained in Below-:

The correct answer to the question 'Of the four books, the red one is the ...' is **B) cheapest**. This is because we are making a comparison among four distinct books. When comparing more than two items, the superlative form of an adjective is appropriate, as it conveys that one item stands out in a specific aspect compared to all the others.

In this case, "cheapest" is the superlative form of "cheap," indicating that the red book has the lowest price among the four books in question. The other options either misuse the comparative form or are grammatically incorrect.

Option A, "more cheaper," is incorrect because "more" is redundant when used with "cheaper," which already indicates a comparative degree. Option C, "cheap," merely describes the red book's cost without making any comparison. Lastly, Option D, "cheaper," is also a comparative form, but it doesn’t imply that the red book is the lowest priced among all four. Thus, "cheapest" is the only choice that accurately reflects that the red book is the least expensive option in this context.