What means service A & Service B for oil service???

 

Per Mercedes manual (2007 C Series):

At 13,000 miles or one year, it's time for Service A, in which your dealer will change your oil and filter, top up a few fluids levels, check front brake pad wear, battery and tires. At 26,000 Service B includes everything from Service A plus climate control dust filter change front and rear brake pad wear and more. And every year or 13,000 you just alternate between Services A and B.

 

don't forget to bend over for the friendly Mercedes service

 

Exactly, Will.
And don't forget to bend over a lot further for that ever-so-reasonable Service B.
The "B" stands for bend. Just be sure you have a home equity line of credit ready.