If you look under the hood of your C230K (mine is an '05), you will see two tubes sticking up on the passenger side near the back of the engine. One will have a red cap on it and the other a black cap which will say something like "for MB shop only". The red capped tube goes to your engine oil pan. If you look carefully, you will see it snake down and enter the top of the engine below. The other tube is the transmission fluid tube. This one goes back further towards the transmission pan. NEITHER of these has a "dipstick" as we know one.
The repair shops and dealerships have a dipstick they can use to check the oil level in case the electronic oil level gizmo isn't working OR they want to change the oil by sucking it out of the engine through the tube from under the hood (many dealers do this now). I still do it the "old" way by taking the plug out from under, etc. So, there it is. Just thought I would answer this since a lot of people have asked.