Before putting an app into production, which step should be taken?

A developer has the following class and trigger code:
public class InsuranceRates { public static final Decimal smokerCharge = 0.01; } trigger ContactTrigger on Contact (before insert) { InsuranceRates rates = new InsuranceRates(); Decimal baseCost = XXX; } Which code segment should a developer insert at the XXX to set the baseCost variable to the value of the class variable smokerCharge?

A developer wants to display all of the picklist entries for the Opportunity StageName field and all of the available record types for the Opportunity object on a Visualforce page. Which two actions should the developer perform to get the available picklist values and record types in the controller? Choose 2 answers.

Which tool can deploy destructive changes to Apex classes in production?

For which example task should a developer use a trigger rather than a workflow rule?