Choose the correct transformation of the given sentence in Indirect S…

The correct answer is Option (2) → The old man asked the conductor if that bus stopped at Karol Bagh.

Changing a yes/no question into indirect speech:

Change	Direct	Indirect	Why
Reporting verb	said to the conductor	asked the conductor	The old man puts a question. So “said to” becomes “asked”.
Joining word	“ ” (quotation marks)	if	The question is answered with yes or no. So “if” (or “whether”) joins it.
Word order	Does this bus stop	that bus stopped	“Does” is dropped. The subject “that bus” comes before the verb, as in a plain sentence.
Tense change	does ... stop	stopped	“Does ... stop” is in the simple present. The simple present is formed with the base form (V1), or V1 + s / es with he, she, it. After the past “said” it becomes the simple past “stopped”. The simple past is formed with the past form of the verb (V2).
Time and place words	this	that	The words are reported later, away from the bus. So “this” becomes “that”.
Full sentence	“Does this bus stop at Karol Bagh?” the old man said to the conductor.	The old man asked the conductor if that bus stopped at Karol Bagh.

A question with “did” moves one step further back: did + verb becomes had + past participle (V3). Example: Riya said to me, “Did you lock the door?” → Riya asked me if I had locked the door.

Why the Other Options are Incorrect?

Option 1: The old man asked the conductor if did that bus stop at Karol Bagh. — Incorrect. “Did that bus stop” keeps the question word order. A reported question drops “did” and puts the subject first.

Option 3: The old man asked the conductor if that bus had stopped at Karol Bagh. — Incorrect. “Had stopped” asks about one past trip. The old man asked about the bus’s usual route, so “does ... stop” becomes “stopped”.

Option 4: The old man asked the conductor whether this bus stopped at Karol Bagh. — Incorrect. “This” is left unchanged. In the report it becomes “that”.