The section presents a multiple-choice question related to chemistry, specifically asking which type of element does not participate in chemical reactions. The options provided are:

A. Kim loại (Metals)  
B. Phi kim (Non-metals)  
C. Khí trơ (Noble gases)  
D. Hợp chất (Compounds)  

The key topic is the classification of elements and their reactivity in chemical reactions, with a focus on identifying the one that does not engage in such reactions. The entities involved are different categories of substances: metals, non-metals, noble gases, and compounds.