Delphinidin- a plant pigment is responsible for the development of . . . . . . . . colour.

The correct answer is B: Blue.
Let's break down why:

Delphinidin is a type of anthocyanidin, which is a natural pigment found in plants.
Anthocyanidins are responsible for a wide range of colors in fruits, vegetables, and flowers.

Specifically, delphinidin tends to produce blue or purple hues.
Think of blueberries, purple grapes, or violet flowers – they often owe their color to delphinidin.

While other pigments contribute to red, orange, and pink colors, delphinidin is most closely associated with blue.