I would say D, since A and B would be highly irrelevant. C sounds like a possible answer, but could still be viewed as irrelevant since it doesn't actually contain info about MP3 players.
Trees produce the oxygen that humans need to breathe
Answer: When permafrost is frozen, plant material in the soil—called organic carbon—can't decompose, or rot away. As permafrost thaws, microbes begin decomposing this material. This process releases greenhouse gases like carbon dioxide and methane to the atmosphere.
Explanation:
Maybe I am misunderstanding the question but some synonyms for tired are sleepy, exhausted, fatigued.
