The answer is D: onomatopoeia.
Fizz means the sound that a liquid makes as bubbles of gas are liberated, making a hissing sound.
It is an onomatopoeia, which is a kind of word that phonetically imitates, implies, suggests or represents the sound that it describes. The most common onomatopoeias in languages refer to the sounds that animals make like “oink” for a pig or “meow” for a cat. Onomatopoeias usually differ from one language to another.