Which sentence uses the correct form for whose vs who’s?

Which sentence uses the correct form for whose vs who’s?

• A. Who's book is this?
• B. Who book is this?
• C. Whose book's this?
• D. Whose book is this?

Answer: (D)

When you want to ask about ownership, use whose. Whose is a possessive pronoun that shows to whom something belongs, and it fits in the structure “Whose [noun] is this?” Here, the sentence that asks who owns the book uses Whose before the noun and then is, forming a natural question about possession: Whose book is this? Who’s, with an apostrophe, is a contraction for who is or who has, and it doesn’t express possession of the book, so it wouldn’t be correct in this context. The form without a possessive word breaks the idea of ownership, and adding an apostrophe after book (Whose book’s this?) isn’t grammatical in standard usage. So the correct choice uses whose to indicate ownership and keeps the expected word order: Whose book is this?

When you want to ask about ownership, use whose. Whose is a possessive pronoun that shows to whom something belongs, and it fits in the structure “Whose [noun] is this?” Here, the sentence that asks who owns the book uses Whose before the noun and then is, forming a natural question about possession: Whose book is this?

Who’s, with an apostrophe, is a contraction for who is or who has, and it doesn’t express possession of the book, so it wouldn’t be correct in this context. The form without a possessive word breaks the idea of ownership, and adding an apostrophe after book (Whose book’s this?) isn’t grammatical in standard usage.

So the correct choice uses whose to indicate ownership and keeps the expected word order: Whose book is this?