— Your silence    on recent events surprises me.    

— I think it's better____too little than say too much.    [ ]

A. say    

B. to say    

C. saying    

D. to be saying

供电企业和用户应如何签订供用电合同，其具体条款有何规定？在什么情况下允许变更或解除供用电合同？