我认为选C更好。
given有两种用法与此句相关。1.后接名词词组，表示原因或条件。
柯林斯：
A. used when indicating a possible situation in which someone has the opportunity or ability to do something. 表示条件
eg. Given patience, successful breeding of this species can be achieved.
B. If you say given something, you mean taking that thing into account. 表示原因
Given the uncertainty over Leigh's future I was left with little other choice.
2. 后接that从句，that可省略，表示原因
If you say given that something is the case, you mean taking that fact into account. 表示原因
eg. Usually, I am sensible with money, as I have to be, given that I don't earn that much.
作为介词用法的given, 牛津、朗文、剑桥词典不管其后跟什么结构，一律解释为原因：taking (sth) into account
由此可见，given表示条件的意义非常有限，即使有，也倾向于后接名词词组而不是分句。
suppose (that), supposing (that), provided (that), providing (that)都可以用作条件状语分句引导词（但没有supposed)； considering其实与given功能相同（见柯林斯词典），都表示原因，所以也不合适。本句需要的是条件概念的分句。“主将从现”结构明显，只能是条件或时间句。