In general, yes, immigration during 1830s to 1840s was vital to the industrialization of America, since it was mostly immigrants who first sought employment in the factories that were an essential element of industrialization.
Civil disobedience is the active, professed refusal of a citizen to obey certain laws, demands, orders or commands of a government. By some definitions, civil disobedience has to be nonviolent to be called 'civil'.
In 320 AD, Chandra Gupta I ascended to power, reuniting and strengthening northern India, while the Tamil kingdoms controlled the south. Option D is correct.
Chandragupta I was a king of the Gupta dynasty, who ruled in northern India. He was the first emperor of the dynasty.
The Gupta Empire was an ancient Indian empire lasting from the mid-to-late 3rd century CE to 543 CE.