money,———has been the least of our worries

money has been the least of our worries
钱现在对我们来说,最不是问题.
显然这已经是完整的句子了.
那么横线上就是个插入语,不起语法作用.
A
important as it is 尽管重要.显然可以.这是典型插入语.
B so important it is that ...这是个倒装句,后面少成分
C是个句子,而且后面也少成分...不行