I have a question.

[cutemina1211]

The legal counsel advised his client to keep his silence as it might be ( )
his case.

A. attributable to
B. injurious

I don't know the exact answer.

and, in the sentence what does "it" indicate?

[mykwyner]

The it refers to his silence, which could be neither attributable to nor injurious [to] his case. I don't think either of those choices is correct.

Is there another choice like, "beneficial [to his case]"? The missing word here should be something that means helpful because that is what a counsel's advice should be.

[Ouisch]

It sounds as though they're implying if the person isn't silent, he may hurt his case. (B. Injurious would be the correct choice then) The "it" would refer to anything the person said, as it can be held against him in a court of law. But that would be a lot of implied information...!