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 test fluorescent bulbs [title] Look for dark areas at the base of the bulb. [step] When bulbs age and have been used for a long time, brown spots will appear. If darkness begins to form at the ends of the tube, the bulb may be near its end. <sep> (A) Look for the phosphorescent lining along the outside of each bulb at the base. This is called " phosphorescent coating. (B) While they may still light, they are wearing out and will die soon. [substeps] If the darkness only forms on one end of a tube light, flip the tube so the darkened end is on the opposite side of the fixture. (C) [title] Identify or remove a covered bulb when it is on display. [step] Fluorescent bulbs that are attached to battery fixtures tend to have a covering or sticker on them that attaches the light to the light bulb. (D) Examine the cap carefully and look for rings. [substeps] While fluorescent bulbs are not inherently dangerous, they can emit uva radiation that is dangerous to humans if ingested.
A:
B