The author mentions the sources of energy such as...

Câu hỏi: The author mentions the sources of energy such as wind, steam, petrol in the first paragraph to__________

A. suggest that electricity should be alternated with safer sources of energy

B. emphasize the usefulness and adaptability of electricity

C. imply that electricity is not the only useful source of energy

D. discuss which source of energy can be a suitable alternative to electricity