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A city replaced the streetlights on its main avenue with new fixtures that each draw less electricity than the old ones. After the replacement, however, the avenue's total monthly electricity use for street lighting was higher than before. Which of the following, if true, most helps to explain this result?
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Correct answer
D
Each lamp uses less power, yet total use rose, so the count of lamps must have grown enough to outweigh the per-lamp saving.
(D) states this directly: the city installed far more efficient fixtures than there were old ones, and many efficient lamps can draw more total power than fewer inefficient ones. (A) repeats the per-fixture efficiency premise, sharpening the puzzle. (B) is about purchase cost, not electricity. (C) describes traffic, irrelevant to the energy total. (E) concerns the old lamps' age. Only (D) reconciles lower per-unit draw with higher total draw.
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