Jack's ______ of black music and performers into a mainstream art form contributed in crucial but not often noted ways to desegregation.

A．transformation

B．assimilation

C．deviation

D．diversion

铁路碎石道砟采石场每生产道砟（）m³（年产量少于（）m³的采石场，时间不超过一年），应按《铁路碎石道砟》（TB/T2140-2008）中表1规定的各项内容进行一次生产性检验。