Final answer:
Salmon spawning is a type of promiscuity, which is a mating system where multiple males and females release gametes at the same time to maximize the chances of fertilization. Therefore, the correct option is C.
Step-by-step explanation:
The reproductive strategy utilized by salmon is known as spawning, where multiple males and females release their gametes into the water to increase fertilization chances. This reproductive process can be classified as promiscuity, which means that there are no exclusive pair bonds or lasting relationships formed between individuals. The process is a reproductive strategy employed by various species to ensure at least some offspring can survive by saturating the habitat with a large number of embryos at once.