The speed of light will be minimum while passing through

Correct answer: (c) glass

Explanation

Speed of light is inversely proportional to a medium's refractive index (v = c/n); a denser medium slows light more.

Among the options, glass has the highest refractive index (about 1.5), versus vacuum and air (≈1) and water (1.33).

Therefore light travels slowest, with minimum speed, while passing through glass.