In our usual speech patterns, we sometimes place clauses in a particular manner for greater emphasis. So, in writing a comma is required for a pause at the place of emphasis. Thus, the correct answer is Option D, no change.
Option A is incorrect, as it does not include the required punctuation.
Option B and C are also incorrect. A semi colon is used between two independent clauses when the coordinating conjunction is omitted whereas, a dash is used to connect closely related independent clauses.