Answer
A. The decrease in predators will cause prey populations to
increase rapidly, disrupting both biotic and abiotic factors
in the ecosystem.
Step-by-step explanation
If the keystone predator is removed, no other species would be able to fill its ecological niche. The ecosystem would be forced to radically change, allowing new and possibly invasive species to populate the habitat. A keystone species that is a predator controls the herbivore populations, which in turn maintains the plant populations and keeps balance.
Although removal of a keystone species will alter the food web on an ecosystem, some parts will persist.