The correct answer is: a) Nyingma sect of Buddhism.
The Namgyal dynasty was a Tibetan royal family that ruled the Kingdom of Ladakh from the 15th to the 19th centuries. They were patrons of the Nyingma school of Tibetan Buddhism, and many of the kings of the dynasty were accomplished Buddhist scholars and practitioners.
The Nyingma school is the oldest of the four major schools of Tibetan Buddhism. It was founded in the 8th century by Padmasambhava, also known as Guru Rinpoche, who is considered the second Buddha. The Nyingma school emphasizes the importance of meditation and the use of mantras and rituals.
The Kagyu school was founded in the 11th century by Marpa Lotsawa, who received teachings from the Indian master Naropa. The Kagyu school emphasizes the importance of lineage and the transmission of teachings from teacher to student.
The Sakya school was founded in the 11th century by Khon Konchog Gyalpo. The Sakya school emphasizes the importance of logic and debate.
The Gelug school was founded in the 14th century by Tsongkhapa. The Gelug school emphasizes the importance of monastic discipline and study.