The section presents a multiple-choice question related to chemistry, specifically focusing on the flammability of elements. The question asks which element has the highest combustibility among the options provided: 

A. Carbon  
B. Oxy (Oxygen)  
C. Hydro (Hydrogen)  
D. Nitơ (Nitrogen)  

Key topics include the properties of chemical elements, particularly their flammability. The entities involved are the four elements listed in the options.