Uranium - Lead Rubidium - Strontium Potassium - Argon Uranium - Strontium
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Geologists frequently use mass spectrometers in determining the relative age of rocks. A spectrometer can differentiate between the ratios of isotopes in rock samples and calculates the radioactive decay involving what two isotopes?
Possibilities:
- Uranium - Lead
- Rubidium - Strontium
- Potassium - Argon
- Uranium - Strontium

Uranium - Lead