answer choice C

@Cammy, happy to help! We do not have enough information to make that claim. Alice never hints at whether or not she believes quotas are common. Instead, she focuses her argument on how competition can benefit consumers, and the prevalence of quotas is irrelevant to this. David fails to address the focus of Alice's argument and instead introduces new information that says quotas are common. Perhaps Alice already knew and agreed with this fact- her argument does not necessarily indicate or offer support otherwise. Therefore, David's argument is flawed because it misses the point of what Alice is saying, and (C) is incorrect. Does that make sense? Please let us know if you have any other questions!

I have a question about assumptions. Every argument probably has an assumption hidden in there somewhere; is every assumption necessary to the argument?

Why is the quota irrelevant to the argument Alice is making. For instance if Japanese manufacturers have quotas domestically this would bolster their demand and allow they to produce more automobiles artificially improving their export power abroad. This seems to me to be implicit in David's response he's pointing out that completely removing trade barriers does not make competition balanced in this case.

David makes an argument that since other countries have quotas the US should as well. Alice's argument focuses on American producers making better quality cars if quotas are removed. While there could be some pricing mechanism involved, Alice's argument only takes quality into consideration which David completely fails to respond to