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 test essential oils for purity [title] Compare the prices of the essential oils. [step] Some flowers or plants that essential oils are derived from require a larger quantity to create one drop of oil. For roses, it takes almost 60 roses to make one drop of oil, and this should be reflected in the price of the oil. <sep> (A) An unusually low price is normally a sign that the oil is diluted in some way, making it less pure. [substeps] If all of the oils from a particular brand are the same price, it is usually indicative of less pure oils. (B) It's important to note that different oils can come in different price ranges for the most potency. For perfume, you may only need a few drops. (C) [title] Examine the types of oils you want to find out about. [step] When purchasing a cultivar of oil, you might want to buy a bottle of different tones to see the cheapest options available. (D) [title] Take your oil through a test kit or agar-ware. [step] Agar-ware is available at major floral or specialty grocery stores, or through heavy duty cleaners.
A