Dark fieid microscopy used in -

Ans. is 'b' i.e., Syphilis o Dark field microscopy is used for spirochetes (for example T pallidum which causes syphilis).Dark ground/ Dark field microscopeo Very slender organisms such as spirochetes and filamentous organs such as flagella are not visible under ordinary illumination.o The contrast in dark field microscopy gives an illusion of increased resolution so that these structures can be seen under the dark field mcroscope.o In dark field microscopy reflected light is used instead of the transmitted light used in the ordinary microscope,o Dark ground (dark field) microscopy is used for :FlagellaSpirochetesRememberComponentMethod of detectionFlagellaFimbriaeSporesCapsuleDark ground microscopeHemagglutinationAcid fast staining by Ziehl-Neelsen techniquey Negative staining by India inky Quellung reaction