Answer: C
C78.7 is the appropriate code because it codes for secondary malignant neoplasm of liver that includes adenocarcinoma of the liver.
Option A is not correct because C18.7 codes for malignant neoplasm of the sigmoid colon. Here, the management of neoplasm in the colon is already done so, this is not appropriate.
Option B is not correct because C20.0 codes for malignant neoplasm in the rectum which is not the diagnosis here.
Option D is not correct because C25.0 is used to code for the malignant neoplasm of the head of the pancreas.