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: Surgery
In Forrest classification visible clot at ulcer base is 
Select and explain. 
A. 1A, B. 2A, C. 2B, D. 3
C: 2B
Answer: C: 2B 
Explanation: FORREST - Classification of upper gastrointestinal hemorrhage
Acute hemorrhage
Forrest IA - Active spurting hemorrhage
Forrest IB - Oozing hemorrhage
Signs of recent hemorrhage
Forrest IIA - Non-bleeding visible vessel
Forrest IIB - Adherent clot
Forrest IIC - Hematin on ulcer base
Lesions without active bleeding
Forrest III - Clean-base ulcers.