Televisions and video players have gold components inside, and it is even used in the instruments ________ enable astronauts to travel...

Televisions and video players have gold components inside, and it is even used in the instruments ________ enable astronauts to travel...

• A. that
• B. which
• C. who
• D. where

Answer: (A)

The main idea here is choosing the right relative pronoun to introduce a clause that defines a noun in a tight, essential way. The instruments are being described by the specific function they have: they enable astronauts to travel. That makes the clause restrictive—the information is necessary to identify which instruments are being talked about. For inanimate objects like instruments, that is the natural choice for a restrictive clause. Using which would usually signal a nonrestrictive (extra) clause and would require a comma before it, subtly changing the meaning by suggesting the information is additional rather than defining which instruments are meant. Who is for people, not things, and where is for places, which don’t fit here.

The main idea here is choosing the right relative pronoun to introduce a clause that defines a noun in a tight, essential way. The instruments are being described by the specific function they have: they enable astronauts to travel. That makes the clause restrictive—the information is necessary to identify which instruments are being talked about. For inanimate objects like instruments, that is the natural choice for a restrictive clause.

Using which would usually signal a nonrestrictive (extra) clause and would require a comma before it, subtly changing the meaning by suggesting the information is additional rather than defining which instruments are meant. Who is for people, not things, and where is for places, which don’t fit here.