This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mechanical injuries, Subject name: Forensic Medicine
Calibre is defined as - 
Select and explain. 
A. Distance between two diametrically opposite grooves, B. Distance between two diametrically opposite lands, C. Distance between two diametrically opposite lands and grooves, D. Ratio of the length and width of the barrel
B: Distance between two diametrically opposite lands
Answer: B: Distance between two diametrically opposite lands 
Explanation: The synopsis of forensic medicine & toxicology ; Dr k.s narayan reddy ; 28th edition ; Pg.no. 122 It is also called gauge . Also refer fig 8-16 (cross section of a rifled barrel)