question about dashes




Which of the following examples uses a dash or dashes​ correctly?


A.


All three areaslong—of the grammar systemlong —​phonology, ​morphology, and syntax will be covered in this textbook.


B.


All three areas of the grammar system​, ph​onology, ​morphology, and​ syntax, will be coveredlong—in this textbook.


C.


All three areas of the grammar systemlong—​phonology, ​morphology, and syntax will be covered in this textbook.


D.


All three areas of the grammar systemlong—ph​onology, ​morphology, and syntaxlong—will be covered in this textbook.