The correct answer is D) The North had organized schools, whereas the South had few organized schools.
A social difference that caused sectionalism in the antebellum era was that the North had organized schools, whereas the South had few organized schools.
The Antebellum is a period before the beginning of the War of 1812 and until the American Civil War (1861-1865). During those years, the country polarized so much between the states that heavily supported slavery and those states that were against slavery. The economy in the North of the United States was based on industry, meanwhile, the economy in the South was based on agriculture and the use of slaves.