Which one of the following environmental conditions would be the most likely reason for evolution to occur?

A winter storm temporarily brought a foot of snow in the arctic.
Rock Pocket Mice and Peppered Moths living in the same area.
A wild fire permanently destroyed all of the low growing plants in a forest.
In the temperate deciduous forest, the leaves turn color and fall off the trees in October.

A wild fire permanently destroying all of the low growing plants in a forest would be the most likely reason for evolution to occur, as it would drastically alter the environmental conditions and selection pressures for the species living in that area. This would likely lead to adaptations in the affected species in order to survive and thrive in the changed environment.