In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".
Q: [header] How to torch weld [title] Put on protective clothing, including long pants and shirt, welder's gloves and eye protection. [title] Work in an open space free of any flammable materials. [title] Turn on the fuel adjustment knob. <sep> (A) [step] This should switch the starter to low fuel. It should then automatically start because any burning gasoline from the spark can prevent it from producing fuel. (B) [step] The knob is located on the shorter of the 2 tanks on the torch. Turn the knob slowly, about 1/2 inch (1.3 cm), to release the gas. (C) [step] This switch is located under the vehicle. [substeps] Keep your torch on for at least 60 minutes. (D) [title] Apply fuel to the weld pan and slowly lower it into the grinding compound. [step] The acidity of the fuel might a affect the readings.
A:
B