Which pigment is involved in photoperiodism?

Correct option is C

Phytochrome is a photoreceptor pigment responsible for sensing light duration and plays a crucial role in photoperiodism (response of plants to light and dark periods).
(a) Chlorophyll: Involved in photosynthesis, not photoperiodism.
(b) Carotenoid: Provides pigmentation and protects against photooxidative damage.
(d) Anthocyanin: Responsible for red, purple, or blue pigments in plants.
Important Point: Phytochrome exists in two forms: Pr (inactive) and Pfr (active), which regulate flowering in short-day and long-day plants.