Texas Was Annexed to the United States as a Result

Texas was annexed to the United States as a result of

A) two-thirds Senate approval of the Treaty of Annexation.
B) a joint resolution enacted by a simple majority in the House and the Senate rather than the two-thirds constitutional supermajority required of all treaties with foreign nations.
C) a presidential executive order by President Tyler.
D) the Treaty of Guadalupe-Hidalgo.
E) a political compromise to admit free-state Iowa at the same time.