What does Mercedes-Benz ab maintenance mean?

Maintenance: engine oil, machine filter, maintenance and lubrication, wiper fluid addition, vehicle oil and water inspection, computer inspection, sewer, tire fastening, tire pressure (5 pieces), chassis inspection (all chassis parts such as suspension brake disc), interior inspection (horn, headlight spray, seat belt, interior lamp, cigarette lighter and other functions), battery inspection and maintenance lamp. B maintenance: air filtration, air filtration, air filtration, air sterilization, skylight lubrication, disassembly-free cleaning of intake throttle nozzle, A.C. maintenance items: actually, it is only A- guarantee, because Mercedes-Benz is AB- guarantee alternation. Over-insurance: There are many things that have been over-insured, except those covered by B, as well as oil-water replacement of the whole vehicle, gasoline filter, a set of pulleys, spark plugs, carbon deposit cleaning and so on.