Answer this correctly and no guessing

why did the cost of slave labor double, even after the invention of the cotton gin?

select the best answer from the choices provided.
a.
the demand for enslaved workers for the cotton fields was high, but the supply of workers was low due to the slave trade ban.
b.
northern enslavers refused to sell their enslaved workers.
c.
enslaved workers were in high demand for tobacco and rice farms.
d.
more enslaved workers were being freed at that point.

an effect of the steamboat's popularity was that people began building canals in the united states and europe. this was done to find another way to transport goods across the country and in that time, transportation using the river was very slow and dangerous. it depended entirely on manpower and the current of the river. that all changed in the late 1700's when steamboats were introduced. they soon revolutionized travel and trade through the river and dominated the waterways. eventually, other means of transportation took over from the steamboats, but there was a time that they the united states to expand to the west.

zheng he was a chinese explorer who lead seven great voyages on behalf of the chinese emperor. his seven total voyages were diplomatic, military, and trading ventures, and lasted from 1405 – 1433. however, most historians agree their main purpose was to promote the glory of ming dynasty china.

explanation:

russia because it is the biggest state

us court of appeals for the 11th circuit