Proteinaceous pigment which controls the activities concerned with light is (a) phytochrome (b) chlorophyll (c) anthocyanin (d) carotenoids.
Option a Phytochrome is a plant pigment that can detect the presence or absence of light and is involved in regulating many processes that are linked to day length (photoperiod), such as seed germination and initiation of flowering. It consists of a lightdetecting portion, called a chromophore, linked to a small protein and exists in two intercovertible forms with different physical properties, particularly in the ability to bind to membranes.