what us the "correct" way to break pieces off a chocolate bar? grooved side up or down? tension vs compression

I know it will make little difference because chocolate is brittle. But let's assume it's out of concrete or steel. The groove reduces the bar's profile, therefore it will more likely break along the groved, so far so good. But does it matter if we reduce the compression component or the tension component of the break? (or in other words, have the grooved side facing up or down) Figure A shows the grooves facing up (like the photo), figure B shows grooves facing down