About RCM

Pls. Solve my Problem from the illustration stated below :-
A Ltd. is a company, who awarded a contract (including material) to B.Pvt. Ltd. amounting = 2.00 Crore
Now B. Pvt. Ltd. gives a work contract to C (Excluding material cost used in work).
B.Pvt Ltd. raised a Running bill to A.Ltd. like that :-
                                                                                        Amt of work = 30,00,000
                                           Service Tax (15% on 40% of Work Amt ) =   1,80,000
                                                               Gross Amt of Running Bill    =  31,80,000
Now C raised a bill (Excluding Material Cost) to B Pvt. Ltd. of           = 15,00,000
C is a unregistered Co. in Service Tax Deptt. but has TIN No.
Now Pls. explain me which type of taxes (as RCM,Vat etc.) would be applicable to C