An effective plotline that moves the story forward should include which element? a. a device that forces unnatural action into the plotb. characters who are secretive or mysteriousc. a conflict that is unresolved at the end of the storyd. foreshadowing that hints at what's coming next

D. Foreshadowing that hints at what's coming next.

An effective plotline that moves the story forward should include foreshadowing that hints at what's coming next. Option D is correct.

Foreshadowing is a literary device by which a writer provides an advance hint of what is to come later in the story. Foreshadowing tends to appear at the beginning of a story, or a chapter, and helps the reader develop great  expectations about the events to come later on in a story.