What's most likely the problem when the car won't shift out of Park ( today )? on 2003 Mercedes-Benz SL500

Took the car to have an oil change and the mechanic came in and said the car wouldn't shift out of Park. It was stuck. Some think it might be the parking cylindroid and others have guessed it will be the shifting assembly.

Asked by for the 2003 Mercedes-Benz SL500