The correct answer is option D The population of foxes would probably decrease.
A food chain can be defined as a linear sequence of organisms through which the nutrients and energy flow as one organisms feeds on the other. Each level of the food chain is called the trophic level. They show organisms starting from the producers and end with consumers or sometimes with detrivores or decomposers. The producers which use solar energy and prepare their food occupy the first trophic level, followed by the primary, secondary, tertiary, quaternary consumers occupying the next trophic level.
In the terrestrial food chain given above, grass → rabbit → fox, the decrease in the any population will effect the other organism at a different trophic level of the food chain. A sudden decrease in the population of rabbits will decrease the population of the foxes at the next trophic level as it is a secondary consumer feeding on the primary consumer which is the rabbit. So, a sudden decrease in the rabbit population will starve the foxes and thus decrease their number in the island.
