What was one of James Polk's first actions as president?

A. finalizing Texas' annexation

B. finalizing California's annexation

C. settling with Britain for Oregon

D. declaring war with Mexico

One of the first actions of James K. Polks as the president was of finalizing Texas' annexation:

Explanation:

Only within a few months after James K. Polks took charge of the office as the 11th president of the United States, he initiated the necessary talks that intended to reach the decision of the annexation of Texas. On the 29th of December 1845, Texas was annexed to become the 28th state of the United States.