Answer: The clause that correctly completes the sentence is D. , which is located in the big city.
Explanation: An adjective clause is a subordinate clause that modifies a noun. It can be restrictive, which means it can provide essential information, or nonrestrictive, which means it can only offer additional information about the noun being modified. Unlike restrictive clauses, nonrestrictive clauses are separated from the rest of the sentence by means of commas. The clause that completes the sentence provided is nonrestrictive because there is a comma after the blank space. In that way, another comma must be added at the beginning of the clause. Moreover, the initial letter of an adjective clause should never be capitalized. The only option that follows these two rules is D. " , which is located in the big city" since, unlike A., it does not add a comma after the word "city" (the comma has already been added after the blank in the sentence provided).
