So far we have done a lot to build a low-carbon economy, but it is _______ ideal. We have to work still harder.

A．next to

B．far from

C．out of

D．due to

在100 mL某一元弱酸（HA）的溶液中，以0.50 mol/L氢氧化钠溶液滴定后得滴定曲线如图所示，下列叙述正确的是(　 　)

A．该弱酸在滴定前的浓度是0.15 mol/L

B．该弱酸稀释10倍后pH为4

C．滴定过程为求滴定终点，最合适的指示剂是酚酞

D．滴定终点时，c(A^－)=c(Na^＋)＞c(H^＋)＝c(OH^－)