I______ thank you too much for all your help to my son while we were away from home.[    ]

A. won't    

B. can't     

C. can      

D. will

独立避雷针（含悬挂独立避雷线的架构）的接地电阻，在土壤电阻率不大于500Ω·m的地区不应大于（）Ω。

A.30

B.20

C.10

D.4