Which of the following statements is true?
a. a human that prepares his/her own meals is a producer.
b. a producer usually obtains food by hunting other organisms.
c. consumers depend upon producers for food.
d. a producer must be a plant.

C. Consumers depend upon producers for food.  A. is false because the meal requires producer's resources, so the human is a consumer.  B. is false because a producer makes its own food, and does not rely on other organisms for food, like consumers do.  D. is false because a producer can even be an animal, and does not absolutely need to be a plant.