Final answer:
The safest way to light a welding torch is to use a spark igniter or a flint lighter to ignite the flammable gas used in the torch.
Step-by-step explanation:
The safest way to light a welding torch is to use a spark igniter or a flint lighter. These tools create a spark that ignites the flammable gas, such as acetylene, used in welding torches. It is important to use a spark igniter or flint lighter because they eliminate the need to use an open flame, reducing the risk of accidents and burns.