The correct answer is B. Silicon Nitride.
Silicon nitride (Si3N4) is a ceramic material that is used as a dielectric in semiconductor devices. It is also used as a barrier layer to protect the active areas of a semiconductor device from etching or oxidation.
Silver nitride (Ag3N) is a white, crystalline solid that is used as a catalyst and in the production of silver metal. It is also used as a semiconductor material.
Hydrofluoric acid (HF) is a strong acid that is used to etch silicon and other materials. It is also used in the production of aluminum and other metals.
Polysilicon (Si) is a semiconductor material that is used in the fabrication of integrated circuits. It is also used in solar cells and other applications.
In the process of selective oxide growth, a chemical is used to shield the active areas of a semiconductor device from etching or oxidation. This allows the oxide to grow only in the desired areas. Silicon nitride is the most common chemical used for this purpose. It is a very effective barrier layer that can withstand the high temperatures and chemicals used in the fabrication process.