See a local shop near you. This is something that if you don't know the basics of what you're looking for, you are just best off seeking professional guidance to ensure the filter is properly replaced.
RepairPal Certified shops can diagnose and repair your 1997 Mercedes-Benz C230. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops