personaly i pick C, A would have to be pretty wide for cable and the draws arent easy to make.
And B isnt realy practical for guitar stuff.
But to be fair neither is C lol.
For all my guitar cables etc. i just use a storage box does the job, maybe you should rethink your idea, as your not going to hit top marks realy for that, i made a lighthouse lamp got a B for it and my coursework was pretty crap so ended up with a F somehow.
A lad in my class built a mini woden 5watt guitar amp he got all the electrics from maplin, he got full marks just an idea.
Richie.