What Accounts for the General Failure of 18th-Century Colonial Revolutions

What accounts for the general failure of 18th-century colonial revolutions against Spanish and Portuguese rule?

A) The various racial and social groups, fearful of unsettling the social hierarchy, failed to act together to unseat the colonial governments.
B) The Spanish reforms were generally so successful that there were few dissatisfied elements in the colonies.
C) Rebel armies enjoyed no success against the military forces of the colonial government.
D) Indians were so little incorporated into American society that they were not interested in changing the political organization of their masters.