Fill in the blank with a relative pronoun:
The earthquake, _________ measured 7.8 on the Richter scale, causing much damage.
A) Which
B) Whose
C) Whom
D) Where

Hint: A relative pronoun is a phrase that introduces a dependent (or relative) clause and relates it to an independent sentence. Since they define or provide additional details regarding the subject of the separate clause they apply to, relative clauses are also known as adjective clauses. The type of relative pronoun to use is determined by the type of noun being mentioned.

Complete answer:
Here we have to explain what kind of relative pronoun would be used to correct the response while using the word earthquake:
Option A: This noun is the antecedent of the relative pronoun, and it appears in the second clause. The subject of the given sentence is "the earthquake," which performs the action "caused" on the object "harm." Since it is commonly used to refer to a thing or case, such as the earthquake, 'which’ is the right pronoun. As a result, option A is right.
Option B: The pronoun 'Whose' is a possessive pronoun, using it one expresses possession by a person. The sentence, however, does not have the meaning of possessive.
Option C: "Whom" is used to refer to persons, or in some cases, to the animal. "Whom" doesn't describe an object or an instance, and the earthquake is an instance, therefore option C is incorrect.
Option D: "Where" refers to a location, not an event, which means that option D is incorrect.

Therefore the correct answer is option ‘A’.

Note: We were able to work out the right answer after a quick clarification of the relative pronoun. A relative pronoun serves as a pronoun since it refers to a noun listed immediately before it. It also serves as a conjunction, as it joins two sentences into a single sentence. The noun ("earthquake") and relative pronoun ("earthquake") are both stated in the first clause.