The correct answer is D. Sonam Wangchuk.
Sonam Wangchuk is the son of Ashi Dorji Wangmo Wangchuk, the eldest daughter of the fourth Druk Gyalpo, Jigme Singye Wangchuck. This makes him a member of the Namgyal dynasty through his mother’s side.
Jaffar Ali is a Pakistani politician who served as the Minister of State for Interior from 2013 to 2018. He is not related to the Namgyal dynasty.
Moti Lal Kemmu is an Indian politician who served as the Chief Minister of Jammu and Kashmir from 1975 to 1977. He is not related to the Namgyal dynasty.
Thupstan Chhewang is a Tibetan politician who served as the Prime Minister of Tibet from 1951 to 1959. He is not related to the Namgyal dynasty.