题目内容：

某固体中含H2O7.62%，K2CO32.38%，KOH90%。若将此固体W(g)加入到98.0g20%的稀硫酸中，再用20.0g10%的KOH溶液恰好中和过量硫酸。将反应后的溶液小心蒸干，可得固体（不含结晶水）的质量是               （     ）                                                                                                                                                                                                                             

A．34.8g           B.30.8g          C.30.8～34.8之间         D.无法计算