The speed of light is minimum while passing through

The speed of light is minimum while passing through glass (option A). In optical materials like glass, light travels slower compared to its speed in vacuum, approximately 299,792,458 meters per second. This reduction in speed is due to the higher refractive index of glass, which causes light to interact more with the material’s atoms and molecules, slowing its propagation. In contrast, in vacuum (option B), light travels at its maximum speed without encountering any medium to impede its velocity. Water (option C) and air (option D) also slow down light compared to vacuum, but to a lesser extent than glass, due to their lower refractive indices. Therefore, the minimum speed of light occurs when passing through materials like glass, where its velocity is noticeably reduced compared to its speed in vacuum, influencing various optical phenomena and applications.