Hi Pawan ,

This is based on Amperes circuital law .by applying it to your problem you may have your answer .being picture was not shown ,it is difficult to answer it.

So apply Amperes law to the problem you can get your answer .

Thanks.

Since diagram is not given so It is difficult to understand Your question, But what I understand is that You wish to find Magnetics field and as long infinite straight wires are given so most probably this question will be solved by Ampere circuital law. Try for it if it gets solved.