Research in Belgium by Jef Van Der Broeck Revealed What

Research in Belgium by Jef van der Broeck revealed what differences in middle-class and working-class speech patterns?

A) Middle-class speakers use the same amount of sentence complexity as working-class speakers, but a larger vocabulary.
B) There was almost no difference in middle-class and working-class speech in Belgium, which is highly unusual.
C) Working-class speakers are more likely to use unusual word choices in order to impress others when they feel uncomfortable because of class differences.
D) Middle-class and working-class sentence complexity is the same for informal speech, but in formal speech situations, middle-class speakers use more complex sentences.