A 70-year-old male presented to the OPD with progressive jaundice for 6 weeks, fever, pruritis along with abdominal pain and significant weight loss. Lab findings reveal, Total S. bilirubin - 22 mg/dL Minimally elevated SGOT/SGPT Increased alkaline phosphatase CT abdomen was done along with ERCP. What is the most common site of this pathology: -