The speed of light in a medium depends on the refractive index of the medium. The higher the refractive index, the slower light travels in that medium. The refractive index is calculated by dividing the speed of light in a vacuum by the speed of light in that medium. As the refractive index given is 2, it means that light travels two times slower in this medium than in a vacuum or air.

Option 1 suggests that the speed of light in this medium is 2 x 10^8 m/s, which would be correct, as this speed is half of the speed of light in air (3 x 10^8 m/s).

Option 2 seems to be a typographical error, as "^" is not a reasonable value.

Option 3 is identical to option 1, so it doesn`t provide any new information.

Option 4 suggests that the speed of light in this medium is the same as in air, which is incorrect, as the refractive index is not equal to 1.

Hence, option 1 is the right answer.