Organisms most likely to be found in extreme environments are
fungi
bacteria
viruses
archaea

bacteria

Explanation:

In the most extreme environments on the planet, such as the surroundings of a volcano, we imagine an extremely hot and toxic place, a desolate place that is not conducive to life. In salt deserts the same image is repeated. However, this first impression may lead us to mistake, these environments have been shown to be rich in life, populated by organisms called extremophiles, which is a group composed of bacteria.

option c is the correct answer.