The caste system is one ancient Hindu belief that still affects modern-day India. Although, it is no longer enforced in modern-day India but the idea of it is still thrown around. I hope I helped in some way, you should look into it a little more so you can have reasons how and why it make still be thrown out there, and how it is still present in modern-day India.
The correct answer is C. Manufacturing.
Explanation
The new technologies developed in the North were on a par with the thousands of inventions that occurred during the Industrial Revolution. For this reason, the economic activity that benefited the most from technological advances was manufacturing, which became massive thanks to them. These new technological inventions allowed the growth of different manufacturing companies that welcomed the economy and efficiency offered by new machines and technology at that time. Therefore, the correct answer is C. Manufacturing.