Sounds are reflected best when bounced off the flat surfaces.
A sound wave is produced when a medium begins to vibrate. When an entity vibrates, a pressure wave is formed, which causes sound.
Since sound waves cannot easily pass through hard surfaces, they bounce off them instead, reflecting back to the source which they first came from.
When sound is reflected off of flat surfaces, it does so most effectively.
Hence the flat surface is the correct answer.
To learn more about the sound wave refer to;
https://brainly.com/question/11797560
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