a) Parent-Child relation ship between the tables that connect them
b) Many to many relationship between the tables that connect them
c) Network model between the tables that connect them
d) None of the mentioned

Answer: a
Explanation: Using the two relationships mother and father provides us a record of a child’s mother, even if we are not aware of the father’s identity; a null value would be required if the ternary relationship parent is used. Using binary relationship sets is preferable in this case.