Which one of the following statements is correct? A: Benzodiazepines directly open chloride channels. B: Benzodiazepines show analgesic actions. C: Clinical improvement of anxiety requires 2 to 4 weeks of treatment with benzodiazepines. D: All benzodiazepines have some sedative effects. E: Benzodiazepines, like other CNS depressants, readily produce general anesthesia.