If there were no hungry problem, the people of the world should have ________ in their daily life.

A．a much happier time

B．a more happier time

C．the happier time

D．much happiest time

将0.1 mol下列物质置于1 L水中充分搅拌后,溶液中阴离子数最多的是（   ）

A．KCl

B．Mg(OH)₂

C．Na₂CO₃

D．MgSO₄