You need to pay attention to the difference between cursors and variables.  Answer B was "Release the resources from a cursor", so it is correct.  The answer would not have been correct if you had used variable instead of cursor.

Even the article you referenced says, "DEALLOCATE removes the association between a cursor and the cursor name or cursor variable. If a name or variable is the last one referencing the cursor, the cursor is deallocated and any resources used by the cursor are freed."