Detailed Instructions: 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".
Q: [header] How to recognize and treat legionnaires' disease [title] Know who gets the disease. [step] Those most at risk includes : [substeps] People 65 years of age or older. Smokers. <sep> (A) Military workers and pharmacists at minimum. Smokers who have worked in the service for at least five years. (B) Those who have a chronic lung disease, like emphysema. People with weakened immune systems from diseases or who take drugs that can suppress the immune system. (C) Very elderly people younger than 25 years or older. Elderly people who have been diagnosed with the disease and are currently infected may have no success with treating the disease. (D) People with years of family history who have recently been born. And anyone from race, gender, and ethnicity who is over 65 or older.
A:
B