What unique action did President Obama take regarding diplomatic relations with Cuba?

President Obama's unique action in regard to diplomatic relations with Cuba was the restoration of direct communication and flights between the two countries. This marked a significant shift in U.S. policy towards Cuba, as it involved reopening diplomatic channels that had been largely closed since the early 1960s, following the Cuban Revolution and the subsequent U.S. embargo.

In December 2014, Obama announced a historic thaw in relations that included plans to re-establish diplomatic ties, which had been severed for more than five decades. This included the reopening of the U.S. embassy in Havana and the relaxation of restrictions on travel and trade. The move aimed to foster a new relationship based on engagement rather than isolation, seeking to normalize diplomatic relations and improve bilateral cooperation. This change was a fundamental aspect of Obama's approach toward Cuba, focusing on constructive engagement and dialogue, which is represented by the restoration of direct communication and flights.

The other choices do not accurately reflect the diplomatic initiatives undertaken; for instance, a trade agreement was not signed, the U.S. embassy was not closed but rather reopened, and there were no military operations initiated against the Cuban government in this context. Obama's actions represent a transformative approach to U.S.-Cuba relations, moving towards more open interactions