Lobbying is

a. an attempt by an individual or group to influence the passage of legislation by exerting indirect pressure, through advertisements and media coverage, on members of Congress or a state legislature.
b. an attempt by an individual or group to influence the passage of legislation by exerting indirect pressure, through phone calls or emails, on members of Congress or a state legislature.
c. the act of working on a re-election campaign.
d. an attempt by an individual or group to influence the passage of legislation by exerting direct pressure on members of Congress or a state legislature.