C

Step 1: Understand the concepts of absolute error and percentage error.
Absolute error refers to the difference between the measured value and the actual value. It gives a direct indication of the error in the measurement in the same units as the measurement itself.
Percentage error is the absolute error expressed as a percentage of the actual value, providing a relative measure of accuracy and allowing for comparison between different measurements or quantities.
Step 2: Both absolute error and percentage error contribute to determining the accuracy of measurement. Accuracy can be evaluated using either method, depending on context.
Conclusion: Since both types of error can be used to assess accuracy, the correct answer is both.
Therefore, the answer is C.