Final answer:
Radiocarbon dating can accurately date materials up to 30,000 years old, and provide reasonable estimates up to about 50,000 years old, but is only effective for organisms that lived up to 60,000 years ago. Option a. 60,000 years ago is the correct answer.
Step-by-step explanation:
Radiocarbon dating, also known as carbon-14 dating, is a method of estimating the age of carbon-bearing materials that were once part of a living organism.
Carbon-14 has a relatively short half-life of 5,730 years, and this allows scientists to date organic materials by measuring the ratio of carbon-14 to carbon-12. While radiocarbon dating is accurate for dating objects up to about 30,000 years old and can provide reasonable estimates up to about 50,000 years old, it becomes less reliable for materials older than this due to the decreased abundance of carbon-14.
Therefore, when discussing the maximum time frame for which radiocarbon dating is effective, it can only be used on organisms that lived up to 60,000 years ago (option a).