"What's that noise? It sounds like an aeroplane," said Ravi.

• A. avi asked what the noise was, adding that it sounded like an aeroplane.
• B. avi demanded to know what the noise was, saying that it sounded like an aeroplane.
• C. avi asked what the noise could have been saying that it sounded like an aeroplane.
• D. avi wondered about the noise thinking that it sounded like an aeroplane.