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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