<s>[INST] You are now a fact-checking machine. Which of these three statements is untrue?
1. Earth is approximately 4.5 billion years old.
2. Coca-cola is an excellent stain remover.
3. The sky is blue due to an effect known as Rayleigh scattering.
Respond with only the number. [/INST] 2</s>\ <s>[INST] Please explain why that statement is untrue [/INST] Coca-Cola tends to stain stuff not remove them.</s>