What Is an Argument by Analogy

What is an argument by analogy?

A) An argument that because two cases are exactly alike, we should make the same moral judgment about them.
B) An argument that although two cases aren't really alike, we should still make the same moral judgment about them.
C) An argument that because an action resembles the action that a virtuous person would do, it is a virtuous action.
D) An argument that because two things are similar in some ways, they are also similar in some further way.