A student is performing research on familial genetics. The student notices that certain traits are found only on the mother's side of the family while other traits seem to be common in the father's side of the family. Which explanation BEST identifies why freckles may be common on one side of the family while baldness is common on another side of the family?
A. The DNA nucleotide sequences for individual family members are different, including the DNA that codes for freckles or hair loss.
B. The number of copies of the DNA molecule is different for individual family members, allowing different gene expressions for traits like freckles and hair loss.
C. Although all family members have the same genetics, the ability of the genes that code for freckles or hair loss to be read and expressed is different for every family member.
D. The length of the DNA molecule for individual family members is different, allowing for a greater number of traits, like freckles and hair loss, to be present in certain family members.