Which of the following events promoted or contributed to slavery in the U. S. ? A. the invention of the cotton gin.
B. Turner's Rebellion.
C. the 13th Amendment.
D. the Emancipation Proclamation.​

The correct answer is A. The invention of the cotton gin.

Explanation

A cotton gin is a machine created during the late 18th century that has the utility of separating cotton fibers from their seeds and other objects attached to it quickly and easily. The invention of this machine contributed to the strengthening of slavery because it allowed the landowners of the south to start the domestic production of cotton cheaply and easily. However, once the export demand for cotton grew in the north and other countries, the landowners of the south acquired more slaves to supply that demand for cotton. This deepened slavery because none of the southern landowners wanted to set free the African-Americans who were bringing them huge profits from their work. So the correct answer is A.

i'd assume india mainly because of how isolated japan was.   plus it is a whole china away.