Why choice B is correct.

The auto maker is acting under the assumption that the only way to make a car more efficient is to make it smaller, and since smaller cars are more dangerous there is no justification or need to making more efficient cars. While not incorrect about the assumption that size matters in terms of efficiency, there are other methods of making a vehicle more efficient that don't involve the shrinking of the vehicle. For instance, a computer system fuel system that runs the vehicle more efficiently and cleanly. With such a system, the cars size wont have to be changed, hence the cars safety wont change AND the car will be more efficient. So B is correct because it provides an alternative method of creating a more efficient car going against the logic of the automaker that the only way to make a car more efficient is to make it smaller.