Official Explanation(C) The passage implies that Alpha believes the reduction in running costs of the new model will, over the life of the car, more than offset the higher purchase price of the car. The savings Alpha foresees are related to gas mileage and the new model's improved safety features.
If gas prices increase, given in choice (A), the offset will occur more quickly. True, Alpha will have had to assume as part of its calculations that buyers of the new model will drive a reasonable number of miles. If they never take the car out of the garage, improved gas mileage will have no financial effect whatever. Driving a reasonable number of miles is an appropriate assumption.
Choice (B) underpins Alpha's claim: reliability could decrease and cost more in the long run or otherwise affect costs. Although it does not mean that the new model will cost less, it is still relevant for calculating costs.
Choices (D) and (E) will clearly help save running costs to compensate for the increase in purchase price.
Choice (C) is the only one that has no bearing on Alpha's claim and is, therefore, the correct answer.