Moirang town is famous for its association with the legend of:

Khamba-Thoibi
Shirui Lily
Dzukou Valley
Loktak Lake

The correct answer is Khamba-Thoibi.

Khamba-Thoibi is a Meitei folktale about a prince and a princess who fall in love. The story is set in Moirang, a town in Manipur, India. Khamba is a brave and strong warrior, while Thoibi is a beautiful and kind princess. The two are from different social classes, but they overcome their differences to be together. The story is a classic love story that has been told for generations. It is a popular story in Manipur and is often performed in dance and drama.

The other options are incorrect because they are not associated with the legend of Khamba-Thoibi. Shirui Lily is a type of flower that is found in Manipur. Dzukou Valley is a valley in Nagaland, India. Loktak Lake is a lake in Manipur.