let us simplify the reasoning given --
% of energy consumed by automobiles = (Average energy consumed by each automobile * No. of automobiles) / (Total energy produced)We are told that this quantity is currently 50%.
However, we are told that efficiency of each car will increase by a factor of 2.
From this the author makes the assumption that
Average energy consumed by each automobile would also be halved.
this makes the assumption that --
1. The amount of fuel consumed/amount of miles driven would be the same -- only then would the average energy consumed would drop by a factor of 2.
Other assumptions concern other terms. We also assume that --
2. No. of automobiles would not change much
3. Total energy produced would not change much
Any answer option that talks about any one of these assumptions should be the correct answer.
Option A - IncorrectElectric cars do consume energy. We are talking about all automobiles.
Option B - IncorrectEven if it does, this talks about "2002". However, the conclusion --
eventually automobiles will consume only 25 percent -- talks about the future.
Option C - CorrectThis is the same as point #1. If the public does increase its usage of automobiles, then we CANNOT say that average energy consumed by each automobile would reduce.
Option D - IncorrectWe are talking about all cars since 2002, not just ONLY those in 2002.
Option E - IncorrectWe are talking about all cars since 2002, not just ONLY those in 2002.
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