A will be the correct answer. Language has been the most significant factor for human development since our beginnings. The skill of language whether written or spoken has been the result of evolutionary needs for humans. It was necessary in order to advance and communicate among each others in complex social ideas.
Scientist agree that all living organisms which have a developed brain have some form of communication.
When humans were able to develop the skill of language, they could communicate and express more complex ideas and thoughts. Language was the most effective tool to accomplish this task.
