A bottle of cooking oil when completely full has a mass of $1.30\,\text{kg}$. After precisely half of the oil has been used, the combined mass of the bottle and the oil left inside is $0.90\,\text{kg}$. What is the mass of the bottle when it is empty?
- A$0.40\,\text{kg}$
- B$0.50\,\text{kg}$
- C$0.65\,\text{kg}$
- D$0.80\,\text{kg}$