The correct answer is A. Tree
Step-by-step explanation:
In ecology, a producer is an organism that can make energy through biological processes, usually through photosynthesis such as plants or algae. This means, producers different to consumers can create food for themselves without eating other organism and because of this, they are always in the base of food chains and are consumed by others. Considering this, the one that is an example of a producer is a tree because this is a plant and therefore can produce own energy and food through photosynthesis which is the main feature of producers.