Frederick Douglass's claim that the Constitution could support emancipation of slavery is best supported by which statement found in the U. S. Constitution?

a. The Congress, whenever two thirds of both Houses shall deem it necessary, shall propose Amendments to this Constitution
b. Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise there of;
c. All legislative Powers herein granted shall be vested in a Congress of the d. United States, which shall consist of a Senate and House of Representatives.
e. Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.