The pigments in chloroplasts that absorb light and typically appear green are primarily chlorophyll (option d). Chlorophyll is crucial for photosynthesis as it captures light energy from the sun, which is necessary for converting carbon dioxide and water into glucose and oxygen.
Chlorophyll absorbs light most efficiently in the blue (around 430-450 nm) and red (around 640-680 nm) wavelengths, while it reflects and transmits green light (around 500-550 nm). This reflection and transmission of green light is why plants appear green to our eyes.
Other pigments, such as carotenoids (option c), can absorb light in the blue-green and violet-red wavelengths and can also contribute to light absorption, particularly under conditions where chlorophyll is less effective, but they do not dominate the light absorption process in healthy green plants. Instead, they provide additional protection against photo-damage and contribute to the spectrum of light available for photosynthesis.
In summary, the green appearance of chlorophyll is due to its specific absorption spectrum, which leaves green light to be reflected, making plants appear green to us.