1) The phrase "Cotton is King" refers to the extremely influential impact that the production of cotton had on the economy of the Southern states during the Antebellum era. Thanks to the invention of the cotton gin, cotton became much easier and cheaper to produce. At this time, cotton was a highly valued resource as it could be used to make textiles.
"Cotton as King" resulted in the increase of the slave population in the South and even benefitted Northern states as well. The ability to access cotton resulted in the growth of Northern textile factories who would then send this manufactured goods to other countries via trade.
3) The South's dependence on just cotton may it extremely vulnerable. This is due to the fact that the South ignore other elements of their economy. This helps us to understand why the South had less railroads and factories when the Civil War began. This focus on cotton resulted in a Southern economy that was unprepared for war.
Well, the Quartering Act required colonists to house and quarter British troops. It would not be C, B, A, or D. At least from all the knowledge I know.
