What does service C include? on 2009 Mercedes-Benz ML350

Mercedes Benz of North Olmsted is telling me that service C will cost me about $400 some, and the agent I called to find out what would be included did not give me a clear answer. Could you help with that and give me an estimate of the charges?

Asked by for the 2009 Mercedes-Benz ML350
The maintenance service indicator message notify you when the next service is required. The services type are A to H, they are based on the estimated time to perform the maintenance; Service A = 1hr, Service B = 2hrs, Service C = 3hrs, ... Service H = 8hrs.

For detailed maintenance service description by mileage or year, find and download the Maintenance Booklet and Owner's Manual here;