According to Political Scientist John Kingdon's Model of the Policy-Making

According to political scientist John Kingdon's model of the policy-making process, what must happen to open a "window of opportunity" in which policy change is possible?

A) The issue must be on the political agenda for at least a year, the two major political parties must have different views on the issue, and one party must be in control of all three branches of government.
B) Two-thirds of major news outlets must report on a political issue, two-thirds of the public must support a specific policy related to the issue, and two-thirds of policy makers must be willing to campaign on the issue.
C) Interest groups must mobilize their memberships, politicians must listen to their constituents, and stakeholders must compromise.
D) A social condition must be defined as a "problem," there must be viable policy alternatives to solving the problem, and the political environment must be conducive to implementing a solution.