We would like you to assess the QUALITY of each of the following argument (discussing Gun Control) and determine if the argument is Valid or Invalid. A valid argument is clearly interpretable and either expresses an argument, or a premise or a conclusion that can be used in an argument for the topic of gun control. An invalid argument is a phrase that cannot be interpreted as an argument or not on the topic of gun control.

Guns don't kill people, people kill people: absolutely true, but guns allow people to kill people with greater efficiency, which is not necessarily a good thing outside of the battlefield.
Valid

Under English common law, the Castle Doctrine was intended to be a narrow exception to the general duty to retreat.
Invalid

Well a lot of good that advice is gonna do these South Carolina people, now that the police have been ordered not to pursue criminals who run from the scene of a crime.

Valid