Just on Race C, I have some observations about DTS in general that may be helpful.
Entering the first chicane you are a sitting duck. Just accept it and race smart. You are always better to concede a position and stay on track than fight and get pushed off. If under pressure, pick your line early and drive to that line. If you take the inside into turn 1, take off enough speed to leave a gap on the apex at turn 2. If you stay on the racing line, stay wide enough that you won't get hit by someone taking the first turn apex.
Never go 2 wide through the first kink. If you're caught on the outside, pull out early.
Never go 2 wide into the esses.
There are lots of usable lines into the right hander before the CoD. Pick one and stick to it. Your goal should be to get the car turned at the apex. The usual racing line makes you vulnerable to dive bombs, but if you brake a bit earlier and let them bomb past, you can make a cutback stick into the CoD.
NEVER TAKE THE CoD 2 WIDE.
The final turn is similar to the right hander into the CoD. Lots of people will take the inside and brake later to try and overtake. If you hang wide and concentrate on a late apex you will often get the place back on exit.
Most of all, the divebombers, late brakers and hyper aggressive drivers at DTS almost always come unstuck somewhere. It's a great track for being smart and playing the long game.