Q: 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 weed killer [title] Start with 2 c (400 ml) of white distilled vinegar. [step] Vinegar contains acetic acid, which effectively kills weeds. Keep in mind that vinegar is non-selective and will kill any living plant it touches, not just weeds. <sep> (A) White vinegar can be used alone, or you can add additional ingredients to the vinegar to make an even stronger solution. [substeps] Avoid using vinegar on or near your lawn, since it will kill the grass. (B) You can also use activated charcoal (a mixture of salt and distilled water) instead of vinegar for worst results. [substeps] You can buy activated charcoal at most grocery stores or online. (C) [substeps] For a strong effect, using a mixture of 50 c (400 ml) of white vinegar and white wine vinegar or more is recommended. Since it can alter the characteristics of the weeds, adding 50 c couldn't be better. (D) [substeps] [title] Use 6 g (100 ml) of ammonia. [step] Vinegar acts as an insecticide, as it kills certain weeds and discourages them from growing again.
A:
A