Bombay Stamp Act, 1958

No, as per my knowledge B can't use the stamp papers if he is not in the transaction.

no it wont as new rules in subregistrears office r  very strict for convencing but in court fees act advocate can use within 6 month stamp papers for court fee on his own name can use for other claints work

For information:

34. Instruments not duly stamped inadmissible in evidence, etc.

No instrument chargeable with duty l[ * * * ] shall be admitted in evidence for any purpose by any person having by law or consent of parties authority to receive evidence, or shall be acted upon, registered or authenticated by any such person or by any public officer unless such instrument is duly stamped 2[ or if the instrument is written on sheet of paper with impressed stamp 3[such stamp paper is purchased in the name of one of the parties to the instrument].