Read the passage.
All over the country of [China] there is a kind of black stone existing in beds in the mountains, which they dig out and burn like firewood. If you supply the fire with them at night, and see that they are well kindled, you will find them still alight in the morning, and they make such fine fuel that no other is used throughout the country. It is true that they have plenty of wood also, but they do not burn it, because those stones burn better and cost less.
–The Travels of Marco Polo,
Rustichello da Pisa
Which conclusions does the passage best support? Choose three correct answers.
China burned coal more than wood for heat.
Marco Polo wrote about a new energy source from China.
China had used up most of its wood by clearing land for farming.
China lacked coal resources that could be easily mined and burned.
Marco Polo helped spread technology and ideas from China to Europe.