—______. I have to make a plan for Clean-Up Day.
A:Sorry, I couldn't
B:Sorry, I can't
C:Sure, I can
D:Sure, I could
由Mg(OH)2和MgO组成的混合物,测得其中含镁元素的质量分数为48%.取该混合物5g,将其投入115g的稀硫酸中恰好完全反应,所得溶液中溶质的质量分数为( )