Sentence:  Members of higher and lower social status often cluster around this nucleus , so that Protestant figures on social class give the impression of spread over <WSD>all</WSD> social classes ; but this is deceptive , for the core of membership is concentrated in a single social and economic stratum . 
Meaning of the word marked with <WSD> tags:  quantifier; used with either mass or count nouns to indicate the whole number or amount of or every one of a class