Final answer:
The question regarding how to decrease gun violence is a policy proposal, which suggests changes to existing policies or the creation of new ones to solve a social issue.
Step-by-step explanation:
The question "What should be done to decrease gun violence?" is asking for specific measures or strategies to address a social issue, which makes it a policy proposal. Such a proposal seeks to establish new rules, regulations, or courses of action with the intention of solving a problem or improving a situation. When confronted with this type of proposal, one would consider various approaches like stricter gun control laws, increased educational campaigns on gun safety, or interventions aimed at mitigating the factors that contribute to gun violence.