While many states on the American continents have made the transition to democracy, the United States, so far, has resisted the transition. Which factor promoting democracy does the United States seem to be missing?

• a. Economic equality: the United States' growth has concentrated wealth and power in the parties' elite, who have a strong incentive to stay in power and resist reform.

• b. Income and resources: the United States' population remains largely poor and uneducated.

• c. International pressures: no major international actor has ever criticized the United States on its human rights record.

• d. Civil society: the United States lacks any significant mobilization by its masses.

• e. All of the above