Step 1: Sarhapā.
Sarhapā was a famous Buddhist tantric saint and poet, regarded as a Buddhatantrācārya.
He contributed to the Vajrayāna tradition. Hence A → II.
Step 2: Dīpaṅkara Śrijñāna.
A renowned scholar associated with the Vikramaśīla Mahāvihāra in Bihar.
He spread Buddhism in Tibet. Hence B → I.
Step 3: Huan Sang.
A Chinese Buddhist monk and traveller who visited India in the 7th century CE.
He studied at Nālandā and left detailed accounts of Indian society, polity, and Buddhism.
Hence C → IV.
Step 4: Buddhaghoṣa.
A 5th-century CE Theravāda Buddhist commentator, famous for writing the Aṭṭhakathās (commentaries) in Pali.
Hence D → III.
Step 5: Conclusion.
The correct matching is (A - II), (B - I), (C - IV), (D - III).