Final answer:
The American Revolution and the Civil Rights Movement are two periods in American history that are actively analyzed for interpretation due to their lasting impact on American society. These events reflect the social dynamics of their times and have led to extensive scholarship and debate.
Step-by-step explanation:
When considering current events in American history undergoing interpretation, option c. The impeachment trial of a U.S. President could be seen as an evolving subject. However, if we consider events that have a more substantial footprint in history and are consistently being re-evaluated by historians, then a. The American Revolution stands out.
Recent scholarly works, like Gordon Wood's The Radicalism of the American Revolution, are actively analyzing this period and its profound social and political transformations, indicating its continuous relevance and the ongoing debates about its impacts.
Similarly, b. The Civil Rights Movement and the leadership within it remain a pivotal era in American history that scholars revisit to understand the complexities of social movements and the significant legislative achievements such as the Civil Rights Act of 1964 and the Voting Rights Act of 1965.
In terms of ongoing research and analysis, the American Revolution and the Civil Rights Movement are two periods that reflect the context of their times and continue to be studied for their wide-ranging impacts. These periods highlight the social dynamics and conflicts of their eras, from the changing conceptions of governance and citizenry during the Revolution to the role of the military and the intersections with the Cold War during the Civil Rights era.