下列说正确的是（  ）。

A．物质的量就是1摩尔物质的质量

B．1 mol水中含有2 mol氢和1 mol氧

C．1 mol气态水比1 mol液态水所含的分子数多

D．3 mol O₂与2 mol H₂O中原子数相等

No one appreciated his work during his lifetime, but______it is clear that he was a great artist.

A．in the aftermath

B．by the time

C．in retrospect

D．in this eventuality