ABC: A  GST registered Firm sell the goods Rs. 240000+GST 18% to XYZ and  incurred Rs.85,000/- towards freight charges of a client XYZ paid to GTA VIP
Ltd .  But XYZ reimbursed Rs.85,000/- to ABC towards Freight charges.
 1.GST is applicable on freight charges , from the angle of ABC ? At what rate? 
2.it is treated as composite supply?
3.who will liable to pay reverse charge ABC or XYZ? 
Kindly provide answer in detail , with applicable sections....