The annual “Royal Kathina Ceremony” is associated with which of the following religions?

The Royal Kathina Ceremony is observed every year by Buddhist. It is observed in only one Buddhist temple outside Thailand and this year the Namphake Buddhist temple of Assam was selected. Kathina offering is an ancient Buddhist Tradition of offering special robe and other necessities to monks who maintain strict discipline of retreat during the rainy season. The main purpose of the ceremony is not merely for religious belief but also to strengthen the relationship between Thailand and other countries.