This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Congo-red with amyloid produces- 
Select and explain. 
A. Blue colour, B. Dark brown colour, C. Brilliant pink colour, D. Khaki colour
C: Brilliant pink colour
Answer: C: Brilliant pink colour 
Explanation: The histologic diagnosis of amyloid is based almost entirely on its staining characteristics. The most commonly used staining technique uses the dye Congo red, which under ordinary light impas a pink or red color to amyloid deposits. Under polarized light the Congo red-stained amyloid shows so- called apple-green birefringence Robbins 9 th edition page no. 156