D is the correct answer. Log data can often be useful in diagnosing or investigating the device it was captured from; it is therefore useful to store the data away from the device where it was harvested, in case something happens to the source device. A is incorrect; if something happens to the source machine, the log data may be affected if it is stored on the source. B is incorrect; log data may be stored underground, aboveground, underwater, in the sky, or in orbit, as long as it is stored securely. C is incorrect; airtight seals do not affect log data positively or negatively.
D is the correct answer. Log data can often be useful in diagnosing or investigating the device it was captured from; it is therefore useful to store the data away from the device where it was harvested, in case something happens to the source device. A is incorrect; if something happens to the source machine, the log data may be affected if it is stored on the source. B is incorrect; log data may be stored underground, aboveground, underwater, in the sky, or in orbit, as long as it is stored securely. C is incorrect; airtight seals do not affect log data positively or negatively.