The correct answer is option C. Most of the bugs will be green.
It is given that the bugs live in the grass land environment, and the color of the grass is green, so, the green bugs would be less located by the predators, hence, their chances of predation are less. The red color bugs can be easily located in the green grass, hence, they will be predated more. As a result of more predation of the red bugs, the green or the mutated bugs would have a advantage to grow and reproduce in the grassland environment.