In which service is the GHT primarily used?

The GHT, or Gasoline Hydrotreater, plays a significant role in refining operations specifically aimed at producing high-quality gasoline. This unit is primarily utilized for the removal of sulfur and other impurities from gasoline feedstocks, ensuring that the final product meets stringent environmental regulations and performance standards. By hydrotreating, the GHT contributes to the reduction of sulfur levels, which is critical as lower sulfur content in fuel helps to minimize harmful emissions when the fuel is burned in engines.

In the context of other choices, while diesel and jet fuel production does involve hydrotreating processes, the specific designation of GHT highlights its focus on gasoline production. Chemical feedstocks can also undergo various refining processes, but they are not the primary function of a GHT. Therefore, the functionality and objectives of the GHT distinctly align with producing cleaner, more efficient gasoline, making it the correct answer.