At 2 years old, the human brain is already 75% of adult weight. It will be still growing and at 6 years old age it will become 90% of adult weight. The skull will also grow at the same rate because it has to accommodate a space for the brain to grow. That is why the suture joint of the skull in children is not completely closed.
This statement giving a clue that there is asexually reproduction (may be binary fission) taking place and the progenies in asexual reproduction are genetically similar to parent cell. So answer is A.
