What Did Jean-Paul Sartre Mean by the Expression "Existence Precedes

What did Jean-Paul Sartre mean by the expression "existence precedes essence"?

A) The soul only enters the body after one is born so that God can ensure each person a soul appropriate to his or her place in life.
B) Since there are no timeless or absolute truths, people must struggle to define their essence after they are born, completely on their own.
C) The immediacy of life and its struggles must take priority over quests for the eternal and salvation.
D) The essence of a life is defined by the environment, such as social position and access to education, into which one is born.