Correct Answer: Phytochrome

Solution : The correct option is Phytochrome.

The plant pigment that primarily absorbs light in the red and far-red regions of the spectrum is known as a "phytochrome." Phytochromes are photoreceptor proteins found in plants that play an important role in a variety of plant processes, including the regulation of growth and development in response to light. Pr (red-light-absorbing form) and Pfr (far-red-light-absorbing form) are the two interconvertible forms of phytochromes. When phytochrome absorbs red light, it undergoes a conversion from the Pr to the Pfr form and when it absorbs far-red light, it converts back to the Pr form.