Under the GST Act, the treatment of transportation as part of a supply depends on how the transportation is linked to the transfer of goods. If Mr. A, a registered dealer, is transferring goods to Mr. C and the transportation is involved in the transaction, transportation can indeed be treated as a supply under GST. However, whether it qualifies as a composite supply or a mixed supply will depend on how the transaction is structured.
In this case, if the transportation of goods is bundled with the supply of goods, and the transfer of goods cannot be completed without the transportation (i.e., transportation is an integral part of the transaction), it could be treated as a composite supply. If the goods are the principal supply, GST will be applied based on the rate of the goods, and transportation will be treated as an ancillary service.
For example, if Mr. A is selling goods to Mr. C and the delivery (transportation) is included in the deal, transportation would be seen as a part of the overall supply of goods. As the goods are the principal supply, the transportation service will be treated as an incidental service to the sale of the goods, and GST will be levied on the goods, with transportation included in the same tax rate.
In your scenario, if the transportation is not bundled with the goods and can be considered a separate supply (for instance, if Mr. A and Mr. C separately agree on the transportation service), then the transportation would be treated as part of a mixed supply. In such cases, GST would be levied on both the goods and the transportation separately. The highest GST rate applicable among the goods and the transportation service will apply.
Conclusion: In this case, if the transportation is part of a bundled deal and is considered necessary for the supply of goods, it will be treated as a composite supply, with the goods being the principal supply. If the transportation is offered separately, it would be treated as a mixed supply, where GST will be applied separately to the goods and the transportation, with the highest applicable rate being applied to the entire supply. This distinction helps determine how GST should be applied, depending on whether the transaction involves a natural bundle of goods and services or independent supplies provided together.