Explanation:

The transfer of data from the CPU to peripheral devices is achieved through 'Interfaces'. An interface, in this context, refers to the communication standards, protocols, and the associated electronic circuitry that enable different hardware components or devices to interact and exchange data. Computer ports (option b) are the physical connectors where these interfaces are exposed, allowing peripherals to be physically attached. However, the actual mechanism of data transfer, including the electrical signals and data formatting, is governed by the underlying interface (e.g., USB interface, PCI Express interface). Option (a) 'Modems' are used for network communication over long distances, not for direct CPU-to-peripheral transfer. Option (d) 'Buffer memory' is temporary storage used to synchronize data flow between devices of different speeds, but it is not the primary means by which data transfer is achieved. Thus, 'Interfaces' (c) provides the most comprehensive explanation of the underlying mechanism.