Need help please. It's urgent. ..about the meaning of metaphor......Choose the best meaning for the underlined metaphor. " Freedom may come at a cost, but it is worth the price."

I am heading out tomorrow morning. I can’t tell you where I am going, only that you will not hear from me for a while. I promise to be in touch as soon as possible. It was the right thing to do. We are fighting for a cause that we all should hold dear to our hearts. Freedom may come at a cost, but it is worth the price.

a) War makes people poor.
b) Freedom requires much sacrifice.
c) Fighting for freedom costs a lot of money.
d) Nobody knows what it will take to attain freedom.