Sodium Carbonate, Na₂CO₃(s), Can Be Prepared by Heating Sodium Bicarbonate

Sodium carbonate, Na₂CO₃(s) , can be prepared by heating sodium bicarbonate, NaHCO₃(s) . 2NaHCO₃(s)
Na₂CO₃(s) + CO₂(g) + H₂O(g) K_p = 0.23 at 100ºC
If a sample of NaHCO₃ is placed in an evacuated flask and allowed to achieve equilibrium at 100ºC, what will the total gas pressure be?

A) 0.46 atm
B) 0.96 atm
C) 0.23 atm
D) 0.48 atm
E) 0.11 atm