Which Did Southern Leaders Hope to Gain by Making the Texas

Which did Southern leaders hope to gain by making the Texas territory part of the United States?

A) Cotton mills could be built along Texas's rivers, decreasing reliance on the North.
B) Southern industrialists would gain access to valuable oil reserves.
C) Forests in northern Texas could help to revive a flagging shipbuilding industry.
D) It would enable a land route to ports on the Pacific Ocean.
E) The territory could potentially be turned into several slave states.