The correct answer is: D. Oxygen and Acetylene
Oxygen and acetylene are the most common gases used in welding. They are used in a variety of welding processes, including gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), and oxyacetylene welding.
Oxygen is a colorless, odorless gas that is essential for combustion. It is used in welding to provide a fuel for the arc and to protect the weld from oxidation. Acetylene is a colorless, flammable gas that is used in welding to provide a high-temperature flame.
Other gases that may be used in welding include argon, helium, and nitrogen. These gases are used to provide shielding for the weld, to improve the quality of the weld, or to reduce the amount of spatter.
Here is a brief explanation of each option:
- Option A: Oxygen and Hydrogen. Hydrogen is a flammable gas that is used in welding to provide a high-temperature flame. However, it is not as common as oxygen and acetylene.
- Option B: Oxygen, Hydrogen, Acetylene and Nitrogen. Nitrogen is an inert gas that is used in welding to provide shielding for the weld. However, it is not as common as oxygen and acetylene.
- Option C: Oxygen, Acetylene and Argon. Argon is an inert gas that is used in welding to provide shielding for the weld. It is more common than nitrogen, but it is not as common as oxygen and acetylene.
- Option D: Oxygen and Acetylene. Oxygen and acetylene are the most common gases used in welding. They are used in a variety of welding processes, including gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), and oxyacetylene welding.