The correct option is D All of the above
The study of inheritance of genetic traits in several generations of a human family in the form of a family tree diagram is called pedigree analysis. The following are the advantages:
(i) It helps in genetic counselling to avoid disorders
(ii) It shows the origin of a trait and flow of a trait in a family
(iii) It is important to know the possibility of a recessive allele that can cause genetic disorders like colour blindness, haemophilia, etc.