The correct answer is C.
An intra-state supply is a supply of goods or services that takes place within a single state. In this case, the supplier is located in Goa and the place of supply is also in Goa. Therefore, this is an intra-state supply.
Option A is not an intra-state supply because the supplier is located in Nagpur and the place of supply is in Mumbai. These two cities are located in different states, so this is an inter-state supply.
Option B is not an intra-state supply because the supplier is located in Kolkata and the place of supply is in Bengaluru. These two cities are located in different states, so this is an inter-state supply.
Option D is not an accurate statement because not all of the options are intra-state supplies. Only option C is an intra-state supply.