答案是：B. who it isI have always been honest and straightforward, and it doesn't matterwho it is I'm talking to.我从来都是诚实、直来直去的，无所谓跟谁交谈（跟谁交谈我都如此）。解释：A. who is it 不能用， 因为这是个问句形式，it doesn't matter后面不跟问句。C. it is who 不能用，因为it doesn't matter 后面跟单个词或句子，后面的这个 句子的结构是 it is somebody (that) I'm talking to 用who来代替somebody...
