<em>D. The March on Washington increased public support for civil rights legislation</em>
Explanation:
<em>Speaking on behalf of another person, thing or place is called political advocacy</em>. An example of advocacy is when a non-profit organisation works to help the women suffering from domestic abuse and are unable to speak for themselves.
The group or organisation that tries to influence the government but doesn't hold post in the government is called political advocacy. Group and Peer advocacy are some types of advocacy.
