Read the passage and answer the following question:
A ray of light that travels obliquely from one transparent medium into another will change its direction in the second medium. The extent of the change in direction that takes place in a given pair of media may be expressed in terms of the refractive index. The refractive index is also related to?the relative speed of propagation of light in different media.
If the refractive index of four different media X1, X2, X3, and X4?is given in the table below, answer the questions using and analysing the table given below:

MediumX1X2X3X4Refractive index1.361.521.642.42If light travels from one medium to another, in which of the following cases the change in speed will be minimum