Answer :
The pedigree's purpose is to understand patterns of inheritance in organism. Examination of the pedigree utilizing the standards of Mendelian legacy can decide if a characteristic has an overwhelming or passive example of legacy. Families are frequently built after a relative harrowed with a hereditary issue has been distinguished.
The purpose of pedigree is to trace the ancestory. Therefore, the correct answer is B, i.e., to understand the patterns of inheritance in organisms. it helps in knowing that what characters are passed to the offsprings, what disease may be transferred to the offsprings, and also the mode of inheritance of the disease.