The correct options are
A I - Deer, II - Rabbit, III - Frog, IV - Mouse
B I - Dog, II - Squirrel, III - Bat, IV - Deer
In the given image of food web the organisms (I) and (II) are deer and rabbit as they are the primary consumers or herbivores which feed on vegetation or seeds. Organisms (III) is a frog, a secondary consumer feeding on grasshopper and can in turn be eaten by snakes, and organism (IV) is a mouse feeding on the seeds which are eaten by the secondary consumers snakes and hawks.