✅ The correct answer is "whose" because it is a possessive relative pronoun. It shows that the roof belongs to "the old house," indicating possession (the house's roof).

❌ "Which" is used for non-human antecedents and refers to the subject or object of the clause, not possession. For example: "The house, which is very old, needs repairs."

❌ "That" can refer to both people and things but does not indicate possession. It also isn't typically used in non-defining clauses (with commas) in formal writing when "which" is an alternative.

❌ "Whom" is used for people and acts as the object of a verb or preposition within the relative clause. It is not used for inanimate objects or possession.

✅ The correct answer is "which" because it refers to a thing ("The old house") and acts as the subject of the relative clause ("which stood on the hill for centuries").

❌ "Who" is incorrect because it refers to people, not inanimate objects or houses.

❌ "Whose" is incorrect because it is a possessive pronoun, and the clause does not express possession (e.g., "whose roof was damaged").

❌ "Whom" is incorrect because it refers to people and functions as an object pronoun (e.g., "the person whom I met"), not a subject for a thing.

✅ Sentence A correctly uses a non-restrictive relative clause. "Which stands on the hill" provides additional, non-essential information about "The old house" and is correctly set off by commas. "Which" is used appropriately for a non-human antecedent.

❌ Sentence B is incorrect because "who lives in London" is likely non-essential information about "My brother" (as "My brother" usually identifies a specific person). Therefore, it should be set off by commas: "My brother, who lives in London, is coming to visit."

❌ Sentence C is incorrect. While "that" can introduce a relative clause, it is generally not used with commas for non-restrictive (non-essential) clauses; "which" is preferred in such cases. The sentence should ideally be: "The book, which I read yesterday, was very interesting."

❌ Sentence D is incorrect because "whom" is an object pronoun. In the clause "whom is a doctor," the pronoun acts as the subject of the verb "is," requiring the subject pronoun "who." The correct sentence would be: "Sarah, who is a doctor, advised me to rest."

✅ The correct answer is 'whose'. 'Whose' is a possessive relative pronoun used for both people and things, indicating possession or relationship. In this sentence, it shows that the "pages" belong to "the ancient manuscript."

❌ 'Which' is used for things or animals and introduces non-restrictive clauses, but it does not express possession in this context.

❌ 'That' can be used for things, people, or animals in restrictive clauses, but it does not convey possession.

❌ 'Whom' is an objective relative pronoun used for people, referring to the object of a verb or preposition, not to show possession for a thing.

✅ The correct answer is 'which' because the clause "_______ opened downtown last month" is a non-defining relative clause. This clause provides additional, non-essential information about "The new café" and is correctly set off by commas.

❌ 'That' is typically used for defining relative clauses, which provide essential information and are not set off by commas. It cannot be used in a non-defining clause with commas.

❌ 'Who' is a relative pronoun used specifically for people, not for places or things like "the new café."

❌ 'Where' is a relative adverb used to refer to a place, indicating a location, and would be used if the clause modified the location itself rather than the café as a subject (e.g., "The city where the café opened...").