The correct answer is D. All of the above.
Accidental errors are random errors that cannot be predicted or prevented. They are caused by a variety of factors, such as human error, instrument error, and environmental conditions. Accidental errors are usually small, but they can accumulate over time and lead to significant errors in the results of an experiment.
Accidental errors do not follow any definite mathematical law. This means that they cannot be removed by applying corrections to the observed values. Instead, they must be estimated and their effects taken into account when interpreting the results of an experiment.
Accidental errors are generally small. This is because they are caused by random factors that are not always present. However, they can accumulate over time and lead to significant errors in the results of an experiment.
Therefore, the correct answer is D. All of the above.