What type of music piece describes nature

More like music people listen to like yoga or peaceful piano 

In my opinion, there are millions of pieces of music that can describe nature. Firstly, it depends heavily on what stage of nature you are asking to describe. (Spring, Summer, Fall, Winter) 

For example, a calm, sunny day can be described with beautiful, wispy music played by a quartet or flute with a clear, peaceful melody line. 

Contrasting to this, a windy and stormy day can be described with thunderous music with lots of rubato played by an orchestra (specifically highlighting the timpani and string section).

Finally, I would suggest listening to Vivaldi's "The Four Seasons"! This is Vivaldi's view on nature and how he describes it.

Hope this helps!
Feel free to message me if you have any questions!

Iwould say d) signed unknown street singers who brought original songs to record.