单选题 How is slang defined by the author?

A、 Words and phrases accepted by the majority for formal usage.
B、 Words and phrases understood by the majority but not found in standard dictionaries.
C、 Words and phrases that are understood by a restricted group of speakers.
D、 Words and phrases understood by a large number of speakers but not accepted as formal us- ag

【正确答案】 D

【答案解析】第一段中作者已经定义了slang：“refers to words and expressions understood by a large number of speakers but not accepted as appropriate formal usage by the majority”。D项表述符合义意。