Final answer:
The least appropriate tactic that advocates use to gain support is C) suppressing opposing views as it contradicts democratic principles of open discourse.
Step-by-step explanation:
Advocates use several tactics to gain support for their causes, such as raising awareness, building coalitions, and mobilizing the community. These strategies are aimed at creating positive change and engaging with the public to influence policy decisions. The least appropriate answer among the given options is C) Suppressing opposing views. This approach contradicts the democratic values of open debate and the freedom of expression. Advocacy works best when it facilitates conversation and includes diverse perspectives rather than silencing them.