Answer:
C.
Step-by-step explanation:
Reconstruction era was a period in the U.S history that began after the Civil War, and lasted from 1865 to 1877. The era is known so as many efforts were made to reconstruct and reunify the nation.
The key events that occurred during the era includes establishment of Freedmen's Bureau (1865), impeachment trial of Andrew Jackson (1866), and ratification of the 14th amendment (1868).
Therefore, option C is correct.