Sam Houston was a great political figure. He got Texas independence on the day of the Battle of San Jacinto. He was Governor of both Tennessee and Texas. He was a U.S. Senator and a U.S. Congressmen. He was a frontiersmen, statesmen, great orator, and accomplished military man. He is one of the founding fathers of Texas and a great Indian Rights Supporter.
FYI: He started the saying “Remember the Alamo!.
To spread their influence around the world
My best bet would be B. the US and spain both had control over economic trade and stuff.