Darkfield microscopy allows a lower limit of resolution than bright-field microscopy which helps the tiny...

Darkfield microscopy allows a lower limit of resolution than bright-field microscopy which helps the tiny spirochetes to be seen in patient samples. In darkfield microscpy, there is a dark background where directly transmitted light is excluded by a dark-field condenser allowing only scattered light to be focused on the specimen. With dark-field microscopy bacteria appear luminous against a dark background.

Which of the following microscopic techniques is best suited for direct examination of the infectious agent of syphilis?