Why does nato continue to exist after the cold war ended?

a. nato today is the government of the unified nation-state of europe.
b. nato today is the government of the unified nation-state of europe.
c. nato has become a global organization focused on fighting poverty.
d. nato has become a global organization focused on fighting poverty. e. nato has become more of a broad supranational organization.
f. nato has become more of a broad supranational organization.
g. nato today is an economic organization that created a universal currency for all of europe.