The correct answer is option 4: Anthocyanin.

To understand why, let`s first define what a photosynthetic pigment is. Photosynthetic pigments are molecules found in plants and other photosynthetic organisms that absorb light energy and use it in the process of photosynthesis.

Option 1, Chlorophyll, is a primary photosynthetic pigment found in plants. It absorbs mostly blue and red light, reflecting green light, giving plants their green color.

Option 2, Phycobilin, is a photosynthetic pigment found in red algae and cyanobacteria. It helps absorb light in the regions of the spectrum that chlorophyll cannot, allowing these organisms to carry out photosynthesis.

Option 3, Carotenoid, is another type of photosynthetic pigment found in plants and algae. It absorbs light in the blue and green regions of the spectrum and helps transfer the absorbed energy to chlorophyll for photosynthesis.

Option 4, Anthocyanin, is not involved in photosynthesis. It is a pigment responsible for the red, purple, and blue colors in fruits, flowers, and leaves. It functions mainly in attracting pollinators and protecting plants from UV radiation.

Therefore, the correct answer