Final answer:
Photosynthesis is utilized by autotrophs, which include photosynthetic autotrophs such as plants, algae, and cyanobacteria. These organisms convert sunlight and inorganic carbon into food and are essential for ecosystem functionality,the correct option is A).
Step-by-step explanation:
The type of organisms that use photosynthesis are autotrophs. Autotrophs are organisms that can produce their own food using inorganic carbon, with photosynthetic autotrophs, also known as photoautotrophs, utilizing sunlight as an energy source.
On the other hand, heterotrophs are organisms that cannot synthesize their own food and thus depend on other organisms for energy and nutrients. Common examples of autotrophs include plants, algae, and certain bacteria such as cyanobacteria.
These organisms are crucial for ecosystems as they form the base of food chains and contribute to the production of oxygen in the atmosphere.