Which 19th-century president, a champion of Manifest Destiny, provoked the Mexican-American War and secured the Oregon Territory, serving a single term from 1845 to 1849?

• A Andrew Jackson
• B James K. Polk ✓
• C John Tyler
• D Martin Van Buren

Polk is often ranked as one of the most effective one-term presidents, achieving all four of his major goals: acquiring California, settling the Oregon boundary, lowering tariffs, and establishing an independent treasury.