Answer :
Answer: 2 or 3
Explanation:
its probably 2 because if they created instruments then that is a good demonstration of acoustics. if the answer is realistic or has to be what actaully happened then its 3 because they actaully placed marks in caves and theres a good chance they could have done it where theres a strong echo or where sound is carried.
Answer:
thw answers not B i got it wrong on the test
Explanation: