An 80-L rigid tank contains an ideal-gas mixture of 5 g of N2 and 5 g of CO2 at a specified pressure and temperature. If N2 were separated from the mixture and stored at mixture temperature and pressure, its volume would be
(a) 32 L
(b) 36 L
(c) 40 L
(d) 49 L
(e) 80 L