The term producer means the autotrophic plants that makes food for themselves. The primary consumer such as mice feeds on the producer (corn) for their energy requirement. Producers lie at the first level of the food chain. Producers are the blue-green plants that makes food by the process of photosynthesis by using sunlight.
C. producer, the corn creates its own 'food' with photosynthesis. It's easier to remember as a flow chart producer(typically plants)->primary consumer(mostly herbivores)->secondary consumer(predators and other meat eaters) and decomposers(usually fungus) eat basically everything.
the three general classifications are sensory neurons, motor neurons and interneurons. I don't know how they work together to produce a response to an environmental stimulus:( sorry