Which of the following is a method communities may use to gather agreement?

Consensus is the correct method that communities may use to gather agreement. This approach involves a collective decision-making process where all members participate actively, discussing different viewpoints and working together to reach a mutually acceptable outcome. The emphasis is on finding common ground, which fosters collaboration and unity within the community.

In contrast, negotiation may involve compromise and bargaining, but it doesn't necessarily require full agreement from all parties involved. Lobbying typically refers to advocacy efforts aimed at influencing decision-makers or public policies, often without the direct involvement of community consensus. Lastly, pitfalls do not represent a method for gathering agreement; rather, they signify potential challenges or obstacles that might arise during decision-making processes. Thus, consensus is the most relevant term when discussing methods for communities to achieve agreement.