For the Endothermic Reaction A₂(g) 2A(g),a Snapshot of an Equilibrium

For the endothermic reaction A₂(g) 2A(g) ,a snapshot of an equilibrium mixture of A(g) and A₂(g) may look as follows.(Each circle represents 1.0 mol of A atoms,and the volume of the box is 1.0 L.) What is the equilibrium constant K_P for this reaction at 298 K? (R = 0.08206 L • atm/K • mol)

A) 1.3 ×10²
B) 65
C) 0.22
D) 16
E) 5.33