was one of the first arrangers to incorporate written out ensemble sections that alternated with improvised solo parts resulting in an organized call-and-response format for big bands. He also modified preexisting stock arrangements from other popular bands and personalized them for the Fletcher Henderson orchestra.

Don Red-man  

Explanation:

Don Red-man was a great jazz arranger in history. He was a writer along with he was invented jazz big band arrangement. After completion of his graduation degree, he starts music with Billy and after that, he met with Henderson who was a chief arranger. After a few years, Red-man becomes a competitor of Henderson. It was shocking for Henderson. He put his band together till 1941. After that, he worked as a freelancer and arranged a band for the swing era. He was a famous music director. His influential work was between the year of 1920 to 30.  

b) to encourage free trade

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