This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Skin
Diascopy is very helpful in diagnosis of: 
Select and explain. 
A. Cutaneous vasculitis, B. Nevus anemicus, C. Lupus vulgaris, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Ans. d. All of the above (Ref. Rooks textbook of dermatology 7th edition, 5.10)DIASCOPY# Pressing the glass slide or a stiff, clear, colourless piece of plastic onto the skin compresses blood out of small vessels to allow evaluation of other colors.# Useful in- Lupus vulgaris:granulomatous nodules which have transluscent brownish color known as applejelly nodules.- Nevus anemicusiit is a localized area of vasoconstriction, other pigments unaltered. Diascopy of adjacent skin therefore reveals a identical colour to that of the depigmented area.- Diascopy of skin adjacent to vitiligo,in which there is loss of melanin,demonstrates that the vitiligo remains paler.# Application of medium pressure to a spider nevus can compress radiating arterioles and allow visualization of pulsatile flow in the feeding vessel.# In vasculitis lesions are not blanchable.