The correct answer is B. Thailand.
Maha Chakri Sirindhorn is the second daughter of King Bhumibol Adulyadej and Queen Sirikit of Thailand. She is the longest-reigning queen regnant in Thai history. She is also a scholar and has written extensively on a variety of subjects, including Sanskrit.
The World Sanskrit Award is an annual award given to individuals who have made significant contributions to the study and promotion of Sanskrit. The award was established in 2007 by the Sanskrit Academy of India.
The other options are incorrect. Pakistan is a country in South Asia. Australia is a country in Oceania. China is a country in East Asia.