The correct answer is option A
During the course of evolution, the brain size of human beings have increased and it has led to many types of advancements in the human beings. Earlier, the brain size used 2% of the total energy of the body and now it uses 20% of the total energy of the body. As the environment changed and became unpredictable the brain size became large and helped the ancestors to survive.
This brain size can store a lot of information and utilizes a lot more energy and blood flow.