Spectacles used for viewing 3D films are A. Polaroids B. Concave lens C. Convex lens D. Bifocal lens

3D or three-dimensional stereoscopic film is a motion picture that enhances the illusion of depth perception, hence adding a third dimension. The most common approach to the production of 3D films is derived from stereoscopic photography. Polaroids are circularly polarized 3D glasses which uses polarization glasses to create the illusion of three-dimensional images by restricting the light that reaches each eye. There are a variety of Polaroid glasses like Linearly polarised glasses and Circularly polarised glasses.