Which one has the closest meaning for the sentence?

I'm a 10th grade Turkish high-schooler. Today, we had the final English exam but one question confused me:

Choose the closest one for the sentence below:

That red car is the least expensive one of all in store.

a) Every other car is more expensive than the red car.
b) Others are less reasonable than the red car.

Which one would be convenient?

Solution 1:

The answer is A as B does not relate to the cost of the car..

Every other car is more expensive than the red car.

This says that the red car is the cheapest.. It defines the object in comparison 'Every other car' and then continues to explain the context.

Others are less reasonable than the red car.

This could be a multitude of factors why they are less reasonable.. Also it doesn't specifically mention the cars are less reasonable, there is more ambiguity here.

Good luck with your exam!