You will be given a definition of a task first, then some input of the task.
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 laser pointers safely [title] Never point your laser at another person, especially their face. [step] Laser pointers are very useful, but are a serious hazard to the eyes if used improperly. While lasers under five milliwatts are unlikely to cause significant injury, staring directly into the beam can cause a dark spot, or burn, on your retina. <sep> (A) Always and always use an electronic concealing device such as a helmet or visor when using laser pointers. [substeps] Otherwise, use your eyeglasses and goggles when applying laser pointers. (B) The bright light of the beam can also distract someone while driving or operating aircraft. [substeps] Be aware of the beam at all times. (C) [title] Be sure to check your lenses often. [step] Although laser pointers cannot cause serious damage, they can cause a painful electric shock if they are placed in direct contact with someone's eyes. (D) To prevent yourself from burning yourself, try to maintain a relaxed, upright posture. [title] Apply a magnifying glass to the laser.
Output:
B