HOTSPOT
You are creating a web worker for an HTML5 application.
The following tasks must be performed from within the web worker:
Register an event listener for the web worker
Start and stop the web worker
You need to define a function that performs the required tasks.
Which code segment should you use? (To answer, select the appropriate option from the drop-down
list in the answer area.)
Answer: 
To stop worker, we must use self.terminate().
Sorry! Terminate is used in the main page. Close is used inside the worker.
Your own correction is correct haha. When you want to close the Webworker from within its own code you use close(). Do you want to close it from outside the code (your web-code/main-page) then you should use terminate().
http://www.html5rocks.com/en/tutorials/workers/basics/
the answer is right