Which of the following sentences contains an adverb clause?

The correct answer is Option (1) → In the evening the fruit sellers wait where the city buses stop.

Adverb clause of place:

• An adverb clause of place tells where an action happens. It begins with where or wherever, and no noun of place comes just before it.
• Here “where the city buses stop” tells where the fruit sellers wait. It goes with the verb “wait”.

Why the Other Options are Incorrect?

Option 2: This is the hostel room where my father stayed as a student. — Incorrect. The where-clause comes right after the noun “the hostel room” and tells which room. It is an adjective clause. Example: This is the park where we play cricket.

Option 3: Nobody could tell us where the exam hall was. — Incorrect. The where-clause answers “tell us what?”. It is the object of “tell”, so it is a noun clause. Example: Do you know where Rohan lives?

Option 4: Where the new flyover will be built is still not known. — Incorrect. The where-clause is the subject of “is”. A clause that is the subject is a noun clause. Example: Where the keys went is a mystery.