Which is more important in transmitting the sound, the information...

Trick question. As we all know the most important interconnect is from the phono stage to the integrated amp.

Actually IF we are ignoring the OP question it’s the microphone cable.

but since we should be trying to help the OP it’s the connection from your CD player to preamp for both information and sonic shaping ( if neutrality is not your goal )

The one closer to the source, except when it isn't. 

Ha! No! Not even close!

IF we actually answer the OP then it doesn’t matter. Both are equally important. ALL are equally important. For both A and B, which are repetitive anyway since "shaping the sound" (whatever that means) is included in "max information transfer." So the question itself is garbled. But IF we are gonna take it seriously then the question that should have been asked is which one will give me the most improvement. And the answer to that one is: replace whichever one is worse.

Unless by "shaping the sound" he means messing around with it. In that case replace either one, won’t matter, unless one of them is already messing around more the way you like it messed up than the other, in which case keep that one.

How to tell? As always, we don’t know! We can’t tell! You can only listen and decide for yourself! Which is why its a trick question! (Although not really- you have to listen and decide for yourself is ALWAYS the correct answer!)