Which of the following developments demonstrated the Eisenhower administration's difficulty in applying the concept of liberation?

A) The Suez crisis
B) The Lebanon crisis
C) The U-2 incident
D) The Hungarian revolution

The Hungarian revolution demonstrated the Eisenhower administration's difficulty in applying the concept of liberation because although the US supported the revolution, they ultimately did not intervene and prevent Soviet suppression of the uprising. This highlighted the limits of US power in promoting liberation and supporting anti-communist movements. The other options (Suez crisis, Lebanon crisis, U-2 incident) were also significant events during the Eisenhower administration, but did not specifically demonstrate the difficulty in applying the concept of liberation.