A. is your correct answer.
In hemophilia A it’s caused by a mutation in the gene for factor VIII. Hemophilia B is a result in a deficiency in factor IX due to a mutation in its corresponding gene.
In both cases, it is a mutation in the DNA (the macromolecule).
The relationship between the bone and muscle
They then examined the infected cells and found that they contained labeled DNA, Since the phage DNA entered the infected cell, which demonstrated that it makes sense that DNA is the phage's genetic material. A bacteriophage or a phage is a virus that infects and replicates within Bacteria and Archaea. Phages replicate within the bacterium following the injection of their genome into its cytoplasm.