Answer:
B) External light source
Step-by-step explanation:
When setting up oblique lighting to reveal details of a tire track, an external light source is necessary. Oblique lighting is a technique used in photography to reveal surface details and textures by illuminating the subject from the side at an angle. In order to create oblique lighting, a light source needs to be placed at an angle to the subject. The angle of the light will create shadows that highlight the surface features of the subject, making them more visible.
While a flash attached to a camera could be used to provide extra light, it is not necessary for setting up oblique lighting. Ultraviolet and infrared light sources are also not typically used for this technique.