Final answer:
The Wilmot Proviso, introduced by David Wilmot in 1846, sought to ban slavery in territories acquired from Mexico but failed in the Senate, leaving the issue of slavery open to future conflict. The correct answer is option d.
Step-by-step explanation:
The Wilmot Proviso was introduced by Democrat David Wilmot in 1846 and aimed to prohibit slavery in the territories acquired from Mexico following the Mexican-American War. Although it passed the House of Representatives, it failed to pass in the Senate. The proviso sparked a significant debate within Congress, showing the deep divisions between the North and South on the issue of slavery in the newly acquired territories. The failure of the proviso to become law meant that it neither resolved the issue of slavery in the territories nor did it allow it; instead, it left the matter open to further conflict and legislation such as the Compromise of 1850.