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: Forensic Medicine
"First hand knowledge" refers to 
Select and explain. 
A. Opinion of a doctor in cou, B. Handwriting expe, C. Common witness, D. Fingerprint expe
C: Common witness
Answer: C: Common witness 
Explanation: Ans: C. Common witness"Except common witness all other options are expe witnesses".Only the common witness can be considered as having first-hand knowledge in the cou of law.In the cou procedures, this phrase refers to the personal understanding of circumstances and events, which is re-told and explained by a witness in a couroom, during a cou hearing on the concrete lawsuit.In other words, the witness has been an eye-witness of these circumstances or events and so has accepted directly. Therefore they have clear and detailed personal knowledge of it. An example is a statement in affidavits.