What should be done if an incorrect value is written in an observation?

Correct answer: Take the correct measurement and correct it

Scientific observations must be honest and traceable. If a value has been written incorrectly, the record should not be hidden, erased without explanation, or replaced by a guess. The correct response is to check the instrument and procedure, repeat the measurement carefully, and record the corrected value according to the activity's recording rules. If required, the original error should remain visible with a clear correction.

Therefore option D is correct because it relies on new evidence rather than imagination. Deleting the whole table loses useful observations, and guessing creates an unsupported result. A corrected measurement should be made under the same conditions as far as possible. This practice improves accuracy and allows another person to understand how the final observation was obtained.