The correct answer is: B. Upagupta
Upagupta was a Buddhist monk who lived in the 3rd century BCE. He is said to have been the spiritual advisor to Emperor Ashoka, who converted to Buddhism after witnessing the carnage of the Kalinga War. Upagupta is also credited with spreading Buddhism throughout India.
Ambhi was a king who ruled the kingdom of Avanti in the 3rd century BCE. He is said to have been a patron of Buddhism and to have built many Buddhist temples.
Asvaghosha was a Buddhist monk and poet who lived in the 2nd century CE. He is best known for his epic poem “The Life of the Buddha”.
Vasubandhu was a Buddhist philosopher who lived in the 4th century CE. He is best known for his work on Buddhist logic and epistemology.
Ashoka was a Mauryan emperor who ruled over most of the Indian subcontinent in the 3rd century BCE. He is known for his military conquests, as well as for his conversion to Buddhism and his promotion of non-violence.
Ashoka is said to have been particularly influenced by the Buddhist monk Upagupta. Upagupta is said to have been a wise and compassionate teacher who helped Ashoka to understand the true meaning of Buddhism.