换填垫层法处理软土地基，垫层的厚度主要取决于( )。

A．垫层的宽度

B．垫层土的强度

C．垫层下面土层的地基承载力

D．垫层底面处土的自重应力

_______you are,_________mistakes you will make. [ ]

A. The more careful；the fewer

B. The more carefully；the fewer

C.The more careful；the less

D. The more carefully；the less