Final answer:
The Tennessee congressman who supported annexing Texas and occupying the Oregon Territory was James K. Polk. He emphasized territorial expansion in his 1844 presidential campaign and successfully negotiated the Oregon boundary at the 49th parallel during his presidency. Option 3
Step-by-step explanation:
The congressman from Tennessee who strongly supported annexing Texas and occupying the Oregon Territory was James K. Polk.
Polk was a fervent expansionist and a key figure in the election of 1844. He won the presidency by running on a platform that included the annexation of Texas and the acquisition of the Oregon Territory, two regions critical to the United States' territorial expansion at that time. James K. Polk was very vocal about his expansionist objectives and successfully campaigned on the promise to deliver more lands to United States citizens.
During his presidency, Polk engaged in negotiations with Great Britain which ultimately led to accepting the 49th parallel as the boundary between U.S. and British holdings in the Oregon Territory.
This move not only avoided potential conflict with a powerful Britain but also provided the U.S. with the important deepwater port of Puget Sound. Furthermore, the annexation of Texas and the acquisition of Oregon helped maintain the balance between free and slaveholding states momentarily. Option 3