The correct option is B While the cost of running nuclear plants is about the same as for other types of power plants, the fixed costs that stem from building nuclear plants make the electricity they generate more expensive
The sentence presents a contrast using 'while'. The sentence structure is 'While X, Y'. The distinction comes out clearly. The first half of the sentence talks about the similarity- the costs to run nuclear plants compared to the cost of running other type of power plants is the same. Then the second part states the difference: fixed costs from building nuclear plants make the generation of electricity in these plants makes it more expensive for them to generate electricity. However, there are three errors in the sentence. First, the singular verb 'makes' does not agree with the plural subject 'fixed costs'. Second, the use of 'it' three different times in the sentence make the sentence seem convoluted and is confusing. Finally, the use of two 'that' clauses one after the other, both referring to 'fixed costs' again makes the sentence too wordy and convoluted. Option B corrects these errors and makes the structure of the sentence direct and clear. The use of 'more' without 'than is allowed in this option because the comparison comes out clearly even without it- it is quite clear that we are comparing electricity of nuclear plants with the electricity of other power plants in terms of expensiveness. As the other options are not without errors. A has the errors of the original sentence, C lacks parallelism- 'for other types...' is not parallel to anything in the first part of the comparison, option D too lacks error and E has an illogical comparison. Thus, B is the correct answer.