2Z2(g),若 X2、Y2、Z2的起始浓度分别为0.1mol/L、0.3 mol/L、0.2 mol/L,当反应达到平衡后,各物质的浓度有可能是( )
A:c(X2)=0.2 mol/L
B:c(Y2)=0.1 mol/L
C:c(Z2)=0.4 mol/L
D:c(Y2)=0.6 mol/L