And a revision process you should focus on

Shakespeare's purpose is the one stated in option D:

D. He includes the wedding to Paris to add another complication so that the readers will be in suspense as the play unwinds.

Explanation:

A story, be it a novel or a play, is made of complications and conflicts. If everything happened smoothly and in accordance to the characters' plans, there would be no reason to tell the story. It would be boring.

That is why Shakespeare introduces yet another complication in the already so complicated plot of "Romeo and Juliet". As we know, the two fall in love in spite of their families being mortal enemies. They cannot be together publicly, and even have to marry in secret. Life is already tough on these two, and then there comes Paris saying he wants to marry Juliet and her father planning their wedding. This has the audience throwing their hands in the air in frustration and anxiety. Will those two lovebirds never catch a break? What will happen now? The suspense builds.