Which of these was made possible by railroads?
O A. Faster mail delivery.
O B. Mass transportation.
O C. Changes to industry.
O D. All of the above are correct.

D

Explanation:

Although some of those came after others, they all were made better by railroads.

wisdom

explanation:

the fact that that the teachings on the cosmic order comes from, or through, the heart center

if it were me, i would pick c. c is the best answer because it's basically saying go on a non-violent strike for india