Each of the following sentences contains a nonrestrictive clause. Select the sentence that is punctuated correctly.

Reading poetry is relaxing for her which is why she reads each night before bed.

The play which was written by William Shakespeare, is being performed at the local theater.

The amusement park was shut down, which caused the field trip to be rescheduled.

The author, who wrote the short story we just read in class is signing autographs today at the library.