The correct answer is option 1 - Growing of tropical crops.

The equatorial region is characterized by a hot and humid climate, abundant rainfall, and a dense tropical rainforest. These favorable conditions are ideal for the cultivation of a wide variety of tropical crops.

Option 2 - Growing of cereals, is not a major occupation in the equatorial region. Cereal crops, such as wheat and rice, typically thrive in temperate climates with distinct seasons and moderate rainfall. The equatorial region does not experience these conditions, making it unsuitable for the cultivation of cereals.

Option 3 - Growing of citrus fruits, may be a minor occupation in some equatorial regions where the climate is suitable for citrus cultivation. However, it is not the major occupation as tropical crops such as bananas, cocoa, coffee, and rubber are more commonly grown due to their higher economic value and suitability to the equatorial climate.

Option 4 - Animal rearing, is not typically a major occupation in the equatorial region. The dense rainforest and limited grazing land make it challenging to raise large numbers of livestock. Additionally, the focus in the equatorial region is predominantly on crop cultivation rather than animal rearing.

To summarize, option 1 - Growing of tropical crops,