This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Skin loss extending to fascia, muscle and Bone, belongs to which grade of pressure sore? 
Select and explain. 
A. Grade 2, B. Grade 3, C. Grade 4, D. Grade 5
C: Grade 4
Answer: C: Grade 4 
Explanation: Grading of Pressure Sores :
Grade 1 - Non blanchable erythema.
Grade 2 - Prtial thickness skin loss extending to epidermis and dermia.
Grade 3 - Full thickness skin loss extending to subcutaneous tissue.
Grade 4 : Skin loss extends to fascia + muscles + Bone or tendon or Joint.