For the First-Order Reaction, 2N₂O(g)→ 2N₂(g)+ O₂(g), What Is the Concentration

For the first-order reaction, 2N₂O(g) → 2N₂(g) + O₂(g) , what is the concentration of N₂O after 3 half-lives if 0.25 mol of N₂O is initially placed into a 1.00 L reaction vessel?

A) 1.6 × 10^-2 mol L^-1
B) 3.1 × 10^-2 mol L^-1
C) 6.2 × 10^-2 mol L^-1
D) 1.2 × 10^-1 mol L^-1