The correct answer is (a) Central African Republic.
The Equator is an imaginary line that circles the Earth at 0 degrees latitude. It is the longest line of latitude on Earth and divides the Earth into the Northern and Southern Hemispheres. The Equator passes through 13 countries: Ecuador, Colombia, Brazil, Sao Tome and Principe, Gabon, Congo, Democratic Republic of the Congo, Uganda, Kenya, Somalia, Tanzania, and Indonesia.
Central African Republic is a landlocked country in Central Africa. It is bordered by Chad to the north, Sudan to the northeast, South Sudan to the east, the Democratic Republic of the Congo to the south, the Republic of the Congo to the southwest, Cameroon to the west, and Equatorial Guinea to the northwest. The capital and largest city is Bangui.
The Equator passes through the Central African Republic in the western part of the country. The Equator is a significant line for the country because it divides the country into two climatic zones: the tropical rainforest zone to the south and the savanna zone to the north. The Equator also passes through the capital city of Bangui.
The other options are incorrect because they are not countries that the Equator passes through.