Given the task definition and input, reply with output. 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 use ivermectin [title] Use ivermectin against certain worms. [step] Ivermectin is the drug of choice against several different kinds of worms. The two most common worms treated by this medication are strongyloides stercoralis and onchocerca volvulus. <sep> (A) [substeps] Strongyloides sterandrinds are considered normal doses for severe cases of parasites that might have been avoided with the medication. Onchopropyl methylcellulose is also an additive to this medication. (B) [substeps] Strongyloides stercoralis: this worm is prevalent in northern parts of the united states and canada. It is found on soil and prefers warm humid conditions. (C) [substeps] Strongyloides steroid drugs target the stomach lining-doing this provides minimal blockage, with the rotation of the worm and lowering serotonin, which therefore reduces the digestive process in the worm. [title] Learn about the other drugs that were shown to work. (D) [substeps] Strongyloides are those that are found within worms and then paste a barrier barrier to prevent the worm from entering their eggs. Strongyloides stercorindermoids are injected into the worm once every 12 to 36 months.
B