Thank you for the opportunity to help you with your question!
The free soil party was founded by former US president Martin Van Buren in 1848, a political party whose focuses were stopping the expansion of slavery, support for national internal improvement program, support for moderate tariffs designed for revenue only, and support for the enactment of homestead law. So, in this question, the only valid answer would be B, stopping the expansion of slavery.
Martin Van Buren, also known as the red fox or the little magician
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