What important contribution did Paul Whiteman make to the development of jazz?

a. he hired some of the hottest jazz improvisers from New Orleans and Chicago
b. he broke the race barrier by allowing black musicians in his otherwise white groups
c. his groups were a major stylistic influence on the bands led by Duke Ellington and Fletcher Henderson
d. he was one of the first bandleaders to take jazz out of the nightclub and put it in the concert hall

d