Which word is correctly used to connect a dependent clause in the provided context?

In the context of connecting a dependent clause, the word "that" serves to introduce a subordinate clause, allowing it to provide more information about the noun in the main clause. This function makes "that" particularly useful in specifying or clarifying the subject being discussed, integrating the dependent clause seamlessly into the overall sentence structure.

For instance, in a sentence like "The book that I read was fascinating," the clause "that I read" is dependent and specifies which book is being referred to. This relationship clarifies and enriches the meaning of the sentence while properly linking the two clauses.

The other options, while they have their own uses in language, do not function in the same way as "that" does in introducing a defining subordinate clause. "Who" is typically used to refer to people in a similar context but does not encompass the broader range necessary for connecting clauses about objects or concepts. "Which" generally introduces non-defining clauses that provide additional information but do not specify or restrict meaning. "Where," on the other hand, indicates a place and lacks the grammatical utility of linking clauses that "that" provides. Thus, "that" is the most appropriate choice for connecting a dependent clause in this scenario.