What Is the Central Proposition of Existentialism

What is the central proposition of existentialism?

A) That individuals create their own meaning, roles, prescriptions, and values but do not necessarily fit well into these meanings.
B) That human beings are unfamiliar with using free will to their own advantage and therefore make mistakes.
C) That individuals need self-awareness to identify their free will and thus use it for achieving their potential.
D) That individuals are ignorant of free will and when they do have no guidance on how to use it to reach their potential.