In the following diagram which of the answers below is true
     In the following diagram, which of the answers below is true?  Each patient has one or more patient histories.  Each patient has one and only one visit.  Each patient history belongs to one and only one patient.  Both A and C are true  A, B and C are true 
  
  Solution
Here option D is correct both A and C are true.
As the relation between Patient and PatientHistory is one to many , each patient can have one or more patientHistory.
And from PatientHistory to Patient is one to one relationship i.e one PatientHistory will belong to only Patient.

