It can be inferred from the passage that coal became the principal source of electricity in the United States, because it _______. A. required no complicated machinery B. was comparatively

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It can be inferred from the passage that coal became the principal source of electricity in the United States, because it _______.

required no complicated machinery

was comparatively plentiful and inexpensive

was easy to transport

burned efficiently

Giải thích

Đáp án B

Dựa vào thông tin “… created a demand for a cheap, readily available fuel with which to generate large amounts of electric power. Coal seemed to fit the bill…” → có thể suy ra rằng than đá trở thành nguồn điện chính của Hoa Kỳ bởi vì nó tương đối nhiều và không quá đắt đỏ.