Are you talking about background music?

This will change according to the plot of the story

I don’t know what the plot of <> is,

The more popular canon You can refer to the series,

For cello, the key of D major seems to be relatively deep,

For piano, the key of C is relatively light,

After the climax of the second section, there is One section is quite subtle,

Just listen to it and see for yourself, I hope it can help you.