A cause and effect essay or an essay that follows a cause and effect organizational pattern in which the author aims at presenting one particular event and the effects or consequences this event had and the way these elements are connected. Due to this, essays in this type of organization it is usually the author first analyzes the event or cause and then present the consequence or consequences of it. For doing this, the author usually uses transitional words that express cause and effect such as because, therefore, consequently, due to or so then as these show the way one situation is the cause or consequence of other and therefore are appropriate in this type of essay. Considering this, the transitional word or phrase that is most appropriate for an essay organized by cause and effect is "so then" as this is the only transitional word from the options presented that describes an effect of something and therefore can be used to describe the consequences or effects in a cause and effect essay.
The best and most correct answer among the choices provided by the question is the fourth choice. The foreshadowing help readers stay engaged in a story by expanding <span> on the incident that creates the central conflict.</span>I hope my answer has come to your help. God bless and have a nice day ahead!