The equator does not pass through which of the following countries ?

The correct answer is (b). Mexico.

The equator is an imaginary line that circles the Earth at 0 degrees latitude. It divides the Earth into the Northern and Southern Hemispheres. The equator passes through 13 countries: Ecuador, Colombia, Brazil, the Republic of the Congo, Gabon, Equatorial Guinea, the Democratic Republic of the Congo, Uganda, Kenya, Somalia, Tanzania, Indonesia, and Kiribati.

Mexico is located in the Northern Hemisphere. The Tropic of Cancer passes through Mexico, which is the northernmost latitude at which the Sun can be directly overhead at noon.