Taking it slow

We've all heard the phrase "let's take it slow", but what does that mean? 

A.  In the past when I've heard that phrase used I assumed it meant that they wanted to get to know each other before having sex.  Sure, it is important to build that foundation for a good relationship but it is really hard to spend a lot of time with someone and not kiss or want to fool around.  So how long is 'slow'?  Are you supposed to wait X number of dates or so many weeks?  Previous posts I have asked about waiting or not because if you enjoy sex, it is important to know that you are compatible in that department and why waste all that time if it isn't going to work out in the end.

B.   So let's say the line is crossed, you had sex - is slow now thrown out the window entirely because you couldn't wait and subsequent encounters most likely will result in sex (especially in the beginning).  Does 'let's take it slow' now mean I don't want anything serious?

C.   Do guys say "let's take it slow" make it seem like they have good intentions, but it is supposed to be some sort of reverse psychology where because they said it the woman is now ready to jump ahead?

D.    Does he truly like you and not want you to feel pressured into anything and even though he knows he wants a relationship since it is hard to adjust to all of a sudden spending so much time with someone.

E.    Or all of the above.