Which of the following is a strategic disadvantage of oil? 

A)  It destroys nature through oil spills. 
B)  It will be commercially depleted within 90 years. 
C)  It produces more carbon dioxide than any other fuel. 
D)  It can contaminate groundwater supplies.

The fact that oil will be commercially depleted within 90 years is a strategic disadvantage as it means that societies relying heavily on oil will need to find alternative sources of energy in the near future. The other options (A, C, and D) are all environmental drawbacks of oil but do not necessarily impact its strategic disadvantage.