Assam produces a unique variety of lemon known as:

Kaji Nemu
Khasi Mandarin
Soh Synteng
Tezpur Lime

The correct answer is: d) Tezpur Lime.

Tezpur lime is a unique variety of lemon that is grown in the Indian state of Assam. It is a small, round fruit with a thick skin that is yellow when ripe. The flesh of the fruit is sour and acidic, and it is often used in cooking. Tezpur lime is also a popular ingredient in traditional Assamese medicine.

Kaji Nemu is a type of wild plum that is found in the Himalayas. It is a small, round fruit with a red or purple skin. The flesh of the fruit is sweet and juicy, and it is often eaten fresh or used in jams and jellies.

Khasi Mandarin is a type of mandarin orange that is grown in the Khasi Hills of Meghalaya, India. It is a small, round fruit with a thin skin that is orange when ripe. The flesh of the fruit is sweet and juicy, and it is often eaten fresh or used in juices and desserts.

Soh Synteng is a type of wild orange that is found in the Garo Hills of Meghalaya, India. It is a small, round fruit with a thick skin that is orange when ripe. The flesh of the fruit is sour and acidic, and it is often used in cooking. Soh Synteng is also a popular ingredient in traditional Garo medicine.