Concept:Anthocyanins are plant pigments that build up as metabolic by-products and cause floral colour changes.
Explanation:Anthocyanins are water-soluble pigments found in the cell sap of plants.
They are produced in plant cells as secondary metabolites, not as true waste material.
Plants do not excrete them outside the body; instead, they accumulate inside vacuoles.
Since they are retained as metabolic by-products, they are regarded as plant excretory products.
The colour of anthocyanins changes with the
pH of the cell sap.
Acidic cell sap usually produces red shades, while alkaline conditions produce blue shades.
A shift in cell sap
pH therefore causes the observed discoloration of flowers.
Alkaloids, tannins, and resins also serve as plant excretory products but they do not discolour flowers.
Answer:C. anthocyanins