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: Medicine
A 63 - year old man presented with massive and splenomegaly, lymphadenopathy and a total leucocyte count of 17000 per mm3. The flow cytometery showed CD 23 negative and CD 5 positive monoclonal B-cells with bright kappa positively comprising 80% of the peripheral blood lymphoid cells. The most likely diagnosis is - 
Select and explain. 
A. Mantle cell lymphoma, B. Splenic lymphoma with vilious lymphocytes, C. Follicular lymphoma, D. Hairy cell leukemia
A: Mantle cell lymphoma
Answer: A: Mantle cell lymphoma 
Explanation: None