Pick up the one having broadest valley:

Explanation

Option D is correct.The absorption spectrum of chlorophyll a has two peaks and one valley. The peaks are located at wavelengths of 430-470 nm (blue-green) and 660-670 nm (red). The valley is located at a wavelength of 520-530 nm (green). The valley in the absorption spectrum of chlorophyll a is the broadest. This means that chlorophyll a absorbs light least strongly in the green region of the spectrum. This is why plants appear green, because the green light is reflected rather than absorbed. The broadness of the valley in the absorption spectrum of chlorophyll a is due to the structure of the chlorophyll molecule. The chlorophyll molecule has a porphyrin ring, which is a large molecule that is made up of four pyrrole rings that are linked together. The porphyrin ring is hydrophobic, which means that it does not mix well with water. The magnesium atom in the center of the porphyrin ring also makes chlorophylls hydrophobic.The carotenoids with the broadest valley in its absorption spectrum is lutein. Lutein has a valley in its absorption spectrum at a wavelength of 520-530 nm (green). This is the same wavelength that chlorophyll has a peak in its absorption spectrum. The broadness of the valley in lutein's absorption spectrum means that it absorbs light in a wide range of wavelengths around 520-530 nm. This allows lutein to absorb light that chlorophyll does not absorb as well, which helps to extend the range of wavelengths that can be used for photosynthesis. The absorption spectrum of chlorophyll b has the broadest valley. This valley is located at a wavelength of 520-530 nm (green). The broad valley in the absorption spectrum of chlorophyll b is due to the fact that chlorophyll b absorbs light less strongly in the green part of the spectrum than it does in the blue-green and red parts of the spectrum. This is why plants appear green, because the green light is reflected rather than absorbed.