Autotrophs that utilize light as their energy source are

The correct answer is - phototrophs.

Some of the autotrophs are able to convert the electromagnetic energy from the sunlight into chemical energy in the form of reduced carbon (C). The autotrophs that are able to perform this are called phototrophs. The green plants and the algae are the most prominent members of the phototroph autotrophs.

In essence, the autotrophs are producers, meaning that they are able to produce their own food. The phototrophs are the part of the autotrophs that are able to use the sunlight to produce small amounts of ATP as well as the energy carrier NADHP. By producing the ATP and the NADHP the phototrophs manage to produce glucose, or rather sugars, which are actually their food.

we would need to see the picture to answer it