The Age of a Fossil Can Be Estimated by Analyzing

The age of a fossil can be estimated by analyzing the decay of radioisotopes within the accompanying rock. If you suspected a fossil was 100 million years old, which type of radioisotopes would you use to analyze the accompanying rock?

A) Potassium-40/Argon-40 (half-life = 1.3 billion years; useful dating range =100,000-4.5 billion years)
B) Rubidium-87/Strontium-87 (half-life = 47 billion years; useful dating range = 10 million-4.5 billion years)
C) Uranium-235/Lead-207 (half-life = 710 million years; useful dating range = 10 million-4.5 billion years)
D) Carbon-14/Nitrogen-14 (half-life = 5,730 years; useful dating range = 100-50,000 years)
E) Uranium-238/Lead-238 (half-life 4.5 billion years; useful dating range = 10 million-4.5 billion years)