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: Pathology
An undifferentiated malignant tumour on immunohistochemical stain shows cytoplasmic positivity of most of the tumor cells for cytokeratin. The most probable tumor is: 
Select and explain. 
A. Sarcoma, B. Lymphoma, C. Carcinoma, D. Malignant Melanoma
C: Carcinoma
Answer: C: Carcinoma 
Explanation: . Carcinoma