Which of the following did NOT contribute to the Sectional Crisis in the United States?

Which of the following did NOT contribute to the Sectional Crisis in the United States?

a: the end of Millard Fillmore's presidency

b: the Wilmot Proviso

c: actions Congressmen from the North took to undermine the Missouri Compromise

d: the great potential for new slave states south of the 36˚30’ line after the Mexican American War