What did James Polk’s campaign slogan “Fifty-Four Forty or Fight” mean?

A. American legislators estimated the nation needed 5,440 soldiers for a war with Britain.
B. The United States won ownership over Oregon from the British by a vote of 54 to 40.
C. Polk was willing to go to war over the Oregon border at 54 degrees latitude, 40 minutes.
D. The treaty over the Oregon territory expired in 54 years, but Polk wanted it to end in 40.