Which amendment has been used, under the incorporation doctrine, to apply the Bill of Rights to the states?

A - Twelfth
B - Thirteenth
C - Fourteenth
D - Fifteenth

C - Fourteenth

The correct answer is C - Fourteenth Amendment.

The Fourteenth Amendment to the United States Constitution, ratified in 1868, contains a clause known as the "Due Process Clause" and an "Equal Protection Clause." These clauses have been interpreted by the Supreme Court to incorporate most of the protections in the Bill of Rights and apply them to the states. This process is known as the incorporation doctrine. Therefore, the Fourteenth Amendment is the amendment that has been used to apply the Bill of Rights to the states.

The correct answer is C - Fourteenth.

To find the answer to this question, you should have a basic knowledge of the U.S. Constitution and the Bill of Rights, as well as the incorporation doctrine.

The incorporation doctrine refers to the process by which the U.S. Supreme Court has interpreted the Fourteenth Amendment to apply most of the provisions of the Bill of Rights to the states. The Fourteenth Amendment was ratified in 1868 after the Civil War, and its primary purpose was to grant citizenship and equal protection under the law to former slaves. However, it also contains the Due Process Clause and the Equal Protection Clause, which have been used by the Supreme Court to incorporate fundamental rights protected by the Bill of Rights.

Therefore, the amendment that has been used under the incorporation doctrine to apply the Bill of Rights to the states is the Fourteenth Amendment. Thus, the correct answer is C - Fourteenth.