Which of the Following Helps Explain Southern Democrats' Support for Westward

Which of the following helps explain Southern Democrats' support for westward expansion?

A) Southern Democrats wanted to disperse the growing slave population before its numbers threatened white control of the South.
B) Southern Democrats wanted to stimulate the growth of industry and manufacturing.
C) Southern Democrats wanted to relocate poor, undesirable Irish immigrants who had come seeking work in Southern cities.
D) Southern Democrats wanted to resettle hostile southern Indian nations in lands gained from Mexico.