A developer must create a ShippingCalculator class that cannot be instantiated and must include a working default implementation of a calculate method, that sub-classes can override. What is the correct implementation of the ShippingCalculator class?

Assuming that 'name; is a String obtained by an <apex:inputText> tag on a Visualforce page.
Which two SOQL queries performed are safe from SOQL injections? Choose 2 answers

A custom picklist field, Food_Preference__c, exist on a custom object. The picklist contains the following options: 'Vegan','Kosher','No Preference'. The developer must ensure a value is populated every time a record is created or updated. What is the most efficient way to ensure a value is selected every time a record is saved?

A developer working on a time management application wants to make total hours for each timecard available to applications users. A timecard entry has a Master-Detail relationship to a timecard. Which approach should the developer use to accomplish this declaratively?

A developer wants multiple test classes to use the same set of test data. How should the developer create the test data?