For someone most interested in participating in research that is presented to policymakers, the best professional association would be the CRA (Computing Research Association). The CRA focuses on issues related to computing research and its impact on society, and it often engages with policymakers to inform them about the importance of computing research.
While all the options mentioned are relevant to different areas of technology and computing, the CRA specifically addresses the intersection of computing research and policy, making it the most suitable choice for your interest in presenting research to policymakers.