The correct answer is a lot of money or close relationships with executive branch officers.
Lobbying, in politics, is, by definition, any and all practices exercised by people or companies to influence the decision-making spaces of the public power, acting both in the Executive and in the Legislative, being more frequent in this last mentioned sector. The group of people and institutions that seeks to influence public decisions is called a pressure group.
Basically, lobbying is a way of communicating, debating or trying to convince parliamentarians or government executives (in addition to close officials, such as advisers and secretaries) to make a decision to serve particular or general interests.
