"It's always c"

Trying to figure out where the "It's always c" (as displayed on e.g. Fark.com) meme started. I did a Google search for the term. However the results where disappointing. As of now the top result uses the phrase as c  in chocolate. Then comes a song text with chord progressions where the text "It's always" is simply followed by the chord C. Then finally C as in "C:\", the most common hard disk name in MS-DOS and the Wndows shell.

The correct answer is of course that c stands for option c in a multiple choice question.

Which leads up to this question:

What does "C" stand for in the meme/idiom "It's always c"

a) Chocolate

b) A chord progression to C

c) The option c) in a multiple choice question

d) The primary hard disk on a computer running MS-DOS or the Windows shell.

It's not in the startup folder, it's not something that is left open when closing windows, and it's always C:\Program