I play with the default settings. Don't know if A is better than C. I bought this game many years ago and I ever played with scheme C, so it's hard to me to change the control settings. Anyway, the first thing to do in every level is destroy the red circles
That is something I recently started doing. It is hellish if you let the red circles go to the four corners. It is really hard to avoid death at that point.
I didn't read the manual, and didn't even know there was an option screen. So I have been playing with Option C. I switched it last night to A and died very quickly. Option A seems much harder.