Oooh, in my opinion, this is an example of a poorly written exam question. You could use B quite easily. It is the third conditional and would apply here. The writer clearly thinks that adding "now" means that it invalidates the option of B. I would disagree. It could easily be seen as correct and we use that type of language quite commonly. Whoever wrote the exam question has not been clear enough in the question and the answer alternatives.

It's 'B' - would have been. From ef.com: "The type 3 conditional is used to refer to a time that is in the past, and a situation that is contrary to reality. The facts they are based on are the opposite of what is expressed. The type 3 conditional is used to refer to an unreal past condition and its probable past result. In type 3 conditional sentences, the if clause uses the past perfect, and the main clause uses the perfect conditional."

i beg to differ. i secretly believe that the answer is B. pls refer to: http://www.ef-australia.com.au/english-resources/english-grammar/type-3-conditional/ and lemme know what do u think.