GST applicability on GTA - Goods and Services Tax - GST

If A is a GTA who received a contract of transportation of goods from a company called C. Then A subcontracts that transaction to another GTA called B and B delivers the goods to C on behalf of A. B then bills to A and A bills to C. Reverse charge is being paid by C. whether A is liable to pay GST on reverce charge basis based on the bill raised by B to A? (point to remember- one service has been provided in whole situation i.e., transportation of good by B to C on behalf of A)