The adjective in the given sentence is ‘silk’. It is an adjective of substance explains what the noun is made of. Thus option B is correct. On the other hand, an adjective of origin tells you the place a person or thing comes from or the place they belong to, like ‘Mexican hat’ or ‘French flag’. Whereas, an adjective of quantity describes the quantity or amount of something, especially the noun, like ‘some food’ or ‘enough water’. While an adjective of colour describes the colour of things, for example, ‘red cake’ or ‘white dress’. Since the given adjective indicates the substance the dress is made of and not the origin, quantity or colour, options A, C, and D are incorrect.