In the city of Milford, applications for zoning changes go through a two-step process: a review by the planning commission and a final decision by the city council. At step 1, the planning commission reviews the zoning change request and makes a positive or negative recommendation concerning the change. At step 2, the city council reviews the planning commission's recommendation and then votes to approve or to disapprove the zoning change. Suppose the developer of an apartment complex submits an application for a zoning change. Consider the application process as an experiment.

(a) How many sample points are there for this experiment?
(b) List sample points, construct a tree diagram for the experiment.