The Fourteenth Amendment:
a. marked the most important change in the U. S. Constitution since the Bill of Rights.
b. placed into the U. S. Constitution an essential holding of the Dred Scott decision.
c. passed despite the opposition of Charles Sumner.
d. represented a compromise between the moderate and conservative positions on race.

a. marked the most important change in the U.S. Constitution since the Bill of Rights.

Explanation:

The Fourteenth Amendment of the U.S Constitution holds a number of important provisions such as equal protection, privileges and immunities, states' role in the protection of life, liberty, or property, due process, etc.They Fourteenth Amendment has been referred in major cases and have provided a substantial amount of protection to many individuals and citizens of the country.The Fourteenth Amendment was ratified by the states in 1868 after the end of the American Civil War.It gave a number of inspiration to the civil rights movements.