Hi!
The answer would be C. Producer.
Explanation
Based solely on the description given, which states that cyanobacteria are photosynthetic bacteria, it would be appropriate to infer that these would be at the bottom of the food chain, i.e producers.
Producers, or also known as autotrophs, are identified by their ability to produce food to sustain themselves through biochemical processes (such as photosynthesis).
Hope this helps!
