A Storage Tank at STP Contains 30 Kg of Oxygen $\times$

A storage tank at STP contains 30 kg of oxygen (O₂) . If an additional 15 kg of oxygen is added to the tank without changing the temperature, the pressure in the storage tank becomes

A) 0.51 $\times$ 10⁵ N/m².
B) 1.0 $\times$ 10⁵ N/m².
C) 1.5 $\times$ 10⁵ N/m².
D) 2.0 $\times$ 10⁵ N/m².
E) 3.0 $\times$ 10⁵ N/m².