The correct answer is: a) Abohar-Fazilka belt.
The Abohar-Fazilka belt is a region in Punjab that is known for its production of citrus fruits. The climate in this region is ideal for the cultivation of citrus fruits, and the soil is rich in nutrients. The main citrus fruits that are grown in this region are oranges, lemons, and limes.
The Kandi region is a hilly region in Punjab that is not suitable for the cultivation of citrus fruits. The climate in this region is cold and dry, and the soil is not rich in nutrients.
The Central plains of Punjab are a flat region that is not suitable for the cultivation of citrus fruits. The climate in this region is hot and humid, and the soil is not rich in nutrients.
The borders with Himachal Pradesh are a mountainous region that is not suitable for the cultivation of citrus fruits. The climate in this region is cold and dry, and the soil is not rich in nutrients.