Detailed Instructions: Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
Q: Context: Joanna of Julich (died 1394) was the youngest daughter of Duke William II and his wife, Marie of Guelders.
Question: Who is Joanna of Julich's mother?
A:
marie of guelders