How do i call a function from another script in another object

I got to scripts that are in two different objects. I need script ‘A’ to call a function in script ‘B’. and script ‘B’ is in a different game object,
How do I do this?

This is asked WAY to often to not try and search for the answer yourself.

From unity docs:

http://docs.unity3d.com/412/Documentation/ScriptReference/index.Accessing_Other_Game_Objects.html

From unity forums:

http://forum.unity3d.com/threads/calling-function-from-other-scripts-c.57072/

From unity answers:

From YouTube:

and on and on and on.