If John Has Schizophrenia,how Likely Is It That His Dizygotic

Multiple Choice

If John has schizophrenia,how likely is it that his dizygotic twin brother will also have schizophrenia?

A) John's brother will also have schizophrenia.
B) There is a 38% probability that John's brother will have schizophrenia.
C) There is an 18% probability that John's brother will have schizophrenia.
D) John's brother will not have schizophrenia.