<prompt> Marcus Gunn sign is seen inRetinitis pigmentosaRetinal detachmentDiabetic retinopathyHypeensive retinopathy  <response>: Grading of hypeensive retinopathy:Keith and Wegner 1939 have classified hypeensive retinopathy changes into following four grades:_ Grade I: It consists of mild generalized aeriolar attenuation, paicularly of small branches, with broadening of the aeriolar light reflex and vein concealment._ Grade II: It comprises marked generalized narrowing and focal attenuation of aerioles associated with deflection of veins at aeriovenous crossings Salus sign._ Grade III: This consists of Grade II changes plus copper-wiring of aerioles, banking of veins distal to aeriovenous crossings Bonnetsign, tapering of veins on either side of the crossings Gunn sign and right-angle deflection of veins Salus sign. Flame-shaped hemorrhages cotton-wool spots and hard exudates are also present._ Grade IV: This consists of all changes of Grade III plus silver-wiring of aerioles and papilloedema.Ref: Khurana; 4th edition; Pg. 258 