Can someone explain this answer?

Jina, let's take a look at the options. Choice A has nothing to do with the passage, so we can rule it out. Choice B actually strengthens the dealer's argument, since with more information consumers will not be confused anymore. Choice C can also be eliminated, since the case being argued is selling different products under the same model number. Choice E doesn't weaken the dealer's argument, in fact it may strengthen the dealer's case (if they decide to pass the lower advertising cost on to the consumer in terms of lower product cost).

We are left with choice D. Even though the modifications may improve the appliance, releasing the new version before the older versions are phased out of the market is very confusing to the consumers.

Also, it seems that the consumer's complaint is that they don't know if they are getting the same product that their neighbor got when they purchase this new appliance. If the modified version was released earlier, then maybe the version that the neighbor has IS that same modified version. If that is the case, the new consumer could still be buying the same model that the neighbor has or was previously advertised, and thus their worry would be unjustified.