Alexis and Alexander Are Fraternal Twins

Alexis and Alexander are fraternal twins.Boris and Bjorn are identical twins.Alexis and Boris have been diagnosed with schizophrenia.What is the likelihood that Alexander or Bjorn will be diagnosed with schizophrenia as well

A)  Alexander and Bjorn are both likely to be diagnosed with schizophrenia, and their risks are roughly equivalent. 
B)  Alexander is more likely than Bjorn to be diagnosed with schizophrenia. 
C)  Bjorn is more likely than Alexander to be diagnosed with schizophrenia. 
D)  Neither Alexander nor Bjorn is likely to be diagnosed with schizophrenia.