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".

[header] How to make thermite [title] Select your site carefully. [step] Make sure there is nothing that can burn within four meter radius of the reaction. Check that metals with low melting points, such as lead, tin, cadmium, or zinc, aren't near your four meter radius. <sep> (A) [title] Wear a welding mask for complete protection, but wear sunglasses at the very least. [step] In addition to being extremely hot, thermite emits uv radiation that can damage your eyes if not dealt with properly. (B) [substeps] Thermite typically comes in two forms: form and resin. Form builds into resin if it occurs while smoking, coating. (C) Before attempting to make your thermite machine, call and take it out. If the explode in your area doesn't cause huge destruction, put it back in. (D) Metals with high melting points can burn through organic matter called rock, making it toxic. [substeps] Even a mountain that has been fighting gravity might simply burn through it.
A