The "Webservice" keyword...

A developer created an Apex class that makes outbound RESTful callout. The following was created to send a fake response in Apex test methods.

Which method can be called to return this fake response in the test methods?

Given a list of Opportunity records named opportunityList, which code snippet is best for querying all Contacts of the Opportunity's Account?
A)

B)

C)

D)

What tool in the Developer Console contains information on SOQL query Cardinality?

A developer created a Visualforce page that has a custom controller that navigates to an external website after the' command button is pressed. What is the recommended way to test this functionality?