Exclamatory is the answer you are looking for
A) Although the human brain makes up an extremely small percentage of the human body, our control center ensures our safety and survival every day of our lives by guiding the decisions we make. Since it is divided into separate sections that each work for different aspects and purposes, we can safely conclude that while we do not know the entire purpose of our brain, the contribution to humanity it makes guarantees life to continue for many years to come in the future.
D. You need to have a semicolon or it will become a comma splice.
