The correct answer is: B. Phycobilin
Blue-green algae are photosynthetic organisms that contain chlorophyll, a green pigment that captures sunlight energy. They also contain other pigments, called phycobilins, which give them their blue-green color. Phycobilins are water-soluble pigments that absorb light in the red and blue parts of the spectrum. This allows blue-green algae to photosynthesize in environments where there is little sunlight, such as in deep water or in the shade of other plants.
Chlorophyl is a green pigment that is found in all plants and algae. It is responsible for absorbing sunlight energy and using it to convert carbon dioxide and water into glucose and oxygen. Chlorophyl is the most abundant pigment in plants, and it is responsible for the green color of leaves.
Haemoglobin is a protein that is found in red blood cells. It is responsible for carrying oxygen from the lungs to the rest of the body. Haemoglobin is red in color, and it is responsible for the red color of blood.
Therefore, the correct answer is: B. Phycobilin.