In His Prediction of a Growth in the Gap That

In his prediction of a growth in the gap that separated the bourgeoisie and the proletariat-one that would lead to the eventual overthrow of the bourgeoisie-what did Marx fail to take into account?

A) that technological developments that improve profits would be resisted by the workers
B) that a large, heterogeneous, middle class of high-income workers would emerge
C) that a sense of community spirit and caring would emerge among the bourgeoisie
D) that factory owners would invest profits into improving working conditions