Class-based political movements and tensions have not arisen in the United States because of all of the following EXCEPT

a. unions have been weak due to state and national laws that limit their ability to organize.
b. there is a general acceptance that the inequalities in income provide an incentive for the poor to improve themselves.
c. immigration policy has focused attention on cultural differences, thus reducing the salience of class divisions.
d. candidates refrain from addressing the class implications of public policies.
e. the minimal gap between rich and poor in the country.

e