Final answer:
A) phototroph
Prokaryotes that obtain energy from light are known as phototrophs, and more specifically, photoautotrophs, which perform photosynthesis to create organic compounds from carbon dioxide.
Step-by-step explanation:
A prokaryote that obtains energy from light is a phototroph. Specifically, these organisms are photoautotrophs, a group that uses light energy to convert carbon dioxide into organic compounds through the process of photosynthesis. The organisms in this category include certain types of bacteria, like cyanobacteria, which are similar to plants in their ability to use sunlight to synthesize nutrients.