This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Plastic Surgery and Skin Lesions, Subject name: Surgery
In the Clarke's level of tumor invasion of malignant melanoma level 3 refers to: 
Select and explain. 
A. All tumor cells above basement membrane, B. Invasion into reticular dermis, C. Invasion into loose connective tissue of papillary dermis, D. Tumors cell at junction of papillary and reticular dermis
D: Tumors cell at junction of papillary and reticular dermis
Answer: D: Tumors cell at junction of papillary and reticular dermis 
Explanation: Clark's level ( on the basis of depth of invasion): EPIRS 1. Melanoma restricting to epidermis & appendages 2. Invading Papillary dermis without filling it 3. Reach Interface of papillary & reticular dermis 4. Invading reticular dermis 5. Invading subcutaneous tissue.