This math problem is _________ that  one.  [ ]

A. so easy as  

B. as difficult as  

C. much difficult than    

D. less easier than

砂浆冻融试件应在（）水中浸泡两天后取出，用拧干的湿毛巾轻轻擦去表面水分，然后进行编号，称其质量然后量入篮筐进行冻融试验。