問題文
A utility stores only the measured value and a device identifier for each reading. A year later analysts cannot tell which readings came from probes that had been recalibrated, so they cannot decide whether a trend is real. What should have been captured alongside each reading to prevent this?
選択肢
- Each reading should have carried extended retention recording the longer history.
- Each reading should have carried contextual attributes recording the calibration state.
- Each reading should have carried duplicate copies recording the independent store.
- Each reading should have carried finer intervals recording the shorter changes.