Correct Answer:
B. Finding the age
Carbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (14C) to determine the age of carbonaceous materials up to about 50,000 to 60,000 years old. It is widely used in archaeology and geology to find the age of organic artifacts and fossils. Therefore, Finding the age (Option B) is the correct application. Options A, C, and D describe unrelated processes: collecting carbon, hardening diamonds, or melting steel, none of which are the purpose of carbon dating.