Read the passage.
[1] Upon hearing a strange scratching sound at the front door, Frank's aunt and uncle walked hesitantly to the front door. [2] Reluctantly,
they looked out the window and opened it. [3] To their astonishment, a small dog marched into their living room. [4] Without hesitation, it jumped
on the couch, curled up, and promptly fell asleep.
Which revision should be made to correct a vague pronoun?
O 1. Change "they" to "Frank's aunt and uncle" in sentence 2.
O 2. Change "it" to "the door" in sentence 2.
3. Change "their" to "the aunt's and uncle's" in sentence 3.
4. Change "a small dog" to "it" in sentence 3.