Answer:C)Oklahoma
Explanation:Oklahoma did not join the United States because of the Mexican War. Oklahoma joined the union in 1907; California, Utah, and Arizona were all once a part of Mexico. These states, along with Arizona, New Mexico, Nevada and part of Colorado, were purchased by the United States as a part of the treaty ending the Mexican War.
They were all slave states that had remained in the Union and this is what Missouri, Kentucky, Maryland and Delaware had in common during the Civil war. The correct option among all the options that are given in the question is the second option. I hope that this is the answer you were looking for and it helped you.
It is A because it says that blacks were writing for not only African Americans, but to everyone!