A developer is using a third-party JavaScript library to create a custom user interface in Visualforce. The developer needs to use JavaScript to get data from a controller method in response to a user action. How can the developer accomplish this?

Which of the following about Dynamic Apex is incorrect?

What should be added to the setup, in the location indicated, for the unit test above to create the controller extension for the test?
A)

B)

C)

D)

External Id fields

REST uses __________.