Final answer:
Arc welding doesn't include gas welding.
Step-by-step explanation:
Arc welding is a type of welding that uses an electric arc to join metal materials. It involves creating an intense heat at the welding point, which melts the base metal and forms a bond between the two pieces.
Out of the options provided, the one that doesn't include arc welding is Option 1: Gas welding. Gas welding uses a different process that involves the combustion of a fuel gas, such as acetylene, to create a flame that provides the heat for joining metal materials.
Therefore, the correct answer is Option 1: Gas welding.