Mathematics for IGCSE & O level - Estimation (Section 2 - No. 40)

Which of the following is the most accurate way to express the answer to a calculation?

Always giving the answer to the greatest degree of accuracy possible.

Giving the answer to a sensible degree of accuracy.

Expressing the answer to the nearest whole number.

Using a calculator and writing the answer as it appears on the screen.

The answer should be expressed to a sensible degree of accuracy, considering the accuracy of the input values.