Why does the playwright include the family's tragic past?
a) to confuse the audience
b) to entertain the audience
c) to foreshadow tragedy
d) to create a joyful mood

The answer is:

C) to foreshadow tragedy

The writers usually writte about past actions and situations that the characters live are useful to give an idea of the way life treats our characters and how their fortune is set, in this way talking about past tragedies can foreshadow tragedy in the future.

C). To foreshadow tragedy.

Explanation:

The authors employ several tactics or strategies to keep the inquisitiveness and interest of the readers intact and therefore, they keep adding elements that aids to create suspense and fascination among the readers. Inclusion of the details and description of the family's tragic past is one of these tactics that not only 'foreshadows or hints the readers about forthcoming tragedy' but also helps to evoke the desired response(emotions of pity and fear(catharsis)) from them. Thus, option C is the correct answer.

what are your options ?

i would say years or cherry blossoms

the characters in string all have major secrets that they strive to avoid revealing throughout the play.