Answer:
The correct answer is d. DNA polymorphism and disease gene are linked.
Explanation:
DNA polymorphism helps to study the difference in nucleotide sequence of one DNA in comparison to the standard one.
DNA polymorphism is an important tool to analyze the disease that is caused due an alteration of gene sequence leading to genetic mutation.
Now the altered gene sequence is compared with the normally functioning gene to draw a statistical relationship between altered gene sequence that causes disease with peviously discovered DNA polymorphism.