The value of x2−(y−z)2(x+z)2−y2 + y2−(x−z)2(x+y)2−z2+z2−(x−y)2(y+z)2−x2 is = ?x2−(y−z)2(x+z)2−y2 + y2−(x−z)2(x+y)2−z2+z2−(x−y)2(y+z)2−x2 is = ?

• A. -1
• B. 0
• C. 1
• D. None of these