Data Communication

Step 1: Compare the transmission mechanisms of the given media.

(A) Coaxial cable: Transmits electrical signals over a copper conductor. Speed is limited by electrical resistance and interference.
(B) Microwave transmission: A form of wireless transmission (radio waves). Travels at the speed of light in air, but bandwidth is limited compared to fiber.
(C) Radio waves: General wireless transmission. Similar to microwaves, but typically at lower frequencies, offering lower bandwidth.
(D) Optical fibre: Transmits data as pulses of light through thin strands of glass. Light has a very high frequency, allowing for extremely high bandwidth and data rates, close to the speed of light in the medium (glass).

Step 2: Conclude which is fastest. Fiber optic cables offer significantly higher bandwidth and therefore faster data transmission speeds than coaxial cables and wireless options like microwave or radio waves.