You are researching permissible grounds for divorce in the State of Maryland. Assuming each of the following authorities is on point, which would be treated as primary authority?

A. The case of Flanagan v. Flanagan, from Maryland Court of Appeals, B. West's Key Number Digest, Divorce 12, C. MD Code, Family Law, 7-102, D. Am. Jur. Pleading and Practice Forms, Divorce and Separation 78 and E. A Maryland Law Encyclopedia article entitled, "Permissible grounds for divorce governed by statute"