The correct option is D Brassica nigra
Mustard seeds are also known as rapeseeds. There are many varieties of mustard, which come in a wide range of strengths and flavors. Yellow mustard (Brassica alba), Brown Mustard (B. juncea), Black Mustard (B. nigra). The basic taste and heat of the mustard is largely determined by seed type, preparation and ingredients. Black seed mustard is generally regarded as the hottest type.This well-known spice has its use in medicine as a stimulating external application. The rubefacient action causes a mild irritation to the skin, stimulating the circulation in that area and relieving muscular and skeletal pain.