The section presents a multiple-choice question regarding the chemical element with the symbol "Pb." The options provided are:

A. Chì (Lead)  
B. Bạc (Silver)  
C. Đồng (Copper)  
D. Vàng (Gold)  

Key topics include chemical elements and their symbols, specifically focusing on the element lead. The entities involved are the elements lead, silver, copper, and gold.