Task: Instance Class Understanding (ontology: Sciences/Computer_Science)

Which of the following classes does 'G4 (WHO)' belong to as one valid explicit type? Context: A histologic grade for ovarian tumor according to the World Health Organization indicating that the tumor is undifferentiated.

A. histologic grade according to AJCC 7th edition
B. histologic grade according to the Fuhrman Nuclear Grading System
C. histologic grade for ovarian tumor according to the World Health Organization
D. pathologic lymph node stage for lung according to AJCC 7th edition

Answer: histologic grade for ovarian tumor according to the World Health Organization