fill the blanks with the best options:
4. Although trains may use energy more (i) than do automobiles, the latter move only when they contain at least one occupant, whereas railway carriages spend a considerable amount of  time running up and down the tracks (ii) 

 A. lavishly 
 B. efficiently 
 C. routinely 
 or nearly so. 
 D. vacant 
 E. unimpeded 
 F. overlooked Respond with more than 550 words.
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