[单选题]
Two liters of a perfect p;x,ty6* 3kzi x9 ypnmga sk e670k6s*pddqrk bwb71xm6s are at $0 \; ^{\circ}C$ and 1 atm. If the gas is nitrogen, $N_2$, determine the number of molecules.
A. $3.5 \times 10^{22}$
B. $5.3 \times 10^{22}$
C. $4.7 \times 10^{22}$
D. $7.4 \times 10^{22}$