While most speakers are limited to a single regional dialect, a

While most speakers are limited to a single regional dialect, a socially-conscious speaker must employ a variety of styles of speech known as ______.
A、style
B、standard
C、form
D、registers
【正确答案】：D
【题目解析】：While most speakers are limited to a single regional dialect, a socially-conscious speaker must employ a variety of styles of speech known as registers.