Which nation saw a decline in trade with the United States during WWI ?

The most possible answer would probably be Germany, "the American dollar plummeted from 32.9 to 1 in 1919 to 433 billion to 1 by 1924. The paper on which German marks were printed had more value as kindling or children's building blocks than as currency." From History.com (This is the most likely answer for your question,)

lend lease program was passed by congress on march 11, 1941. the president could ship weapons, food, or stuff to any country whose struggle against the axis assisted u.s. defense

option b, all states follow similar rules and legal process is the right answer.

the 14th amendment in the constitution of america was enacted in july 1868, which include the citizenship, due process, and the equal protection under the law. this amendment was a response to the issues related to former slaves following the american civil war.

the citizenship clause granted citizenship to all persons born or naturalized in the u.s,.   due process of clause asserted that states may not deny any person "life, liberty or property, without due process of law and the equal protection clause declared that a state may not deny to any person within its jurisdiction the equal protection of the laws. the above mentioned excerpt from the constitution of the united states, ensures the citizenship,due process, and equal protection under the law.