It can be inferred from paragraph 1 that before the reign of George III there were no sour

It can be inferred from paragraph 1 that before the reign of George III there were no sources of power that

A．were movable

B．were widely available

C．did not disappear during certain seasons of the year

D．could provide continuous power

请帮忙给出正确答案和分析，谢谢！