The correct option is D.
Thomas Edison was an American investor and business man and he had been described as the American greatest inventor, because during his life time he accumulated 1,093 patents. He is the brain behind many devices which had radically changed the way people live their lives today. The devices invented by him include: phonograph, light bubs, moving pictures, electrographic vote recorder, the carbon telephone transmitter, etc.
The early part of the Vedic period, was an age of economic self-sufficiency and consequently there was little scope for an exchange of commodities. All the rural centres were self-supporting. Every house-holder produced the necessaries of life—his farm producing his food-grains and other necessaries, the industry of the women of his household supplied him with his clothing, while the craftsmen attached to the village did the rest. Consequently, there was no inter-dependence between two neighbouring local areas. The surplus product was kept for future consumption. This state of full economic independence did not however last long. Society became complex.
A large section of the community gave up the simple agricultural life; the primitive arts and crafts drew away a large number; owing to these and various other causes, there arose a scope for interchange of commodities between different local areas.
A is poverty b is political reforms
There were a lot of raids in Africa which led Africans to sell those captured to the Europeans for slavery.
Hope this helped hon :)
