Two flasks are connected by a stopcock. Flask A ($2.0\mathrm{L}$) contains $\mathrm{N}{}_2$ at $1.2\mathrm{atm}$ and flask B ($3.0\mathrm{L}$) contains $\mathrm{Ar}$ at $0.80\mathrm{atm}$, both at the same temperature. When the stopcock is opened (temperature constant), the final total pressure is

1. A$1.00\mathrm{atm}$
2. B$0.96\mathrm{atm}$
3. C$2.00\mathrm{atm}$
4. D$0.48\mathrm{atm}$