Pink colour of onion is due to

Answer: Option B

The pink colour of the onion is due to Anthocyanin which belongs to the class of flavonoids.
Red onions contain anthocyanins in their epidermal cells, with the primary component of the 25 anthocyanins produced being cyanidin-3-O-glucoside, although a complex mixture of other cyanidin and peonidin derivatives are also present.