Professionalism and rudeness in email

A pop quiz. [Edited to add: Actually, this is a poll. I really would like to know what y'all do in these situations.]

1. If you receive an email from someone that is not abusive but is gratuitously rude and snarky, and it's an email that you have to answer for various reasons, what do you do?

a. Ignore the rudeness and answer professionally anyway.
b. Address the rudeness in person.
c. Say something about the rudeness in the email itself.
d. I don't care if it's from Bill Gates offering me a million dollars or the university president himself; I don't answer rude emails.

2. If you receive an email like this, what do you say to yourself?

a. "X may be having a bad day, or maybe her feelings were hurt by some unrelated incident, which is why she sent the rude email."
b. "Oh, Y always acts like that; it's just his way of expressing himself."
c. "Who cares about the rudeness? The content has to be answered."
d. "Who cares whether X was having a bad day or if Y is always a rude so-and-so? Writing rude emails is unprofessional."

3. What about abusive emails?

a. Ignore the abuse and address the issue, if there is one in the message.
b. Respond to the issue and make it clear that you won't tolerate the abuse by talking to the person face to face.
c. Respond professionally, but copy your department chair or someone else so as to leave a record of the conversation.
d. Put the person in your killfile and refuse to deal with him or her.

Let's just say inquiring minds want to know.