Final answer:
Option (a), Radiometric dating is the technique that provides an absolute age for a fossil, using the decay rates of radioactive isotopes like carbon-14 to date fossils in years.
Step-by-step explanation:
The type of dating that provides an absolute age for a given fossil is radiometric dating. This method is based on the rate of decay of radioactive isotopes, such as carbon-14, within the fossil or surrounding rock layers. Radiometric dating allows scientists to estimate the age of a fossil in years, giving a definitive age rather than a relative position in the geological timeline.
Different forms of radiometric dating may be used depending on the type of fossil and its age. For example, carbon dating is often used for fossils up to about 60,000 years old. However, for older fossils, other isotopes may be required for accurate dating.
In contrast, relative dating techniques, which place fossils in a sequence without providing a numerical age, are not suitable for determining the absolute age of a fossil. Therefore, option a) Radiometric dating is the correct answer to the student's question.