With reference to the Indian History, Alexander Rea, A. H. Longhurst, Robert Sewell, James Burgess and Walter Elliot were associated with

• (a) Archaeological excavations — Correct. Alexander Rea, A.H. Longhurst, Robert Sewell, James Burgess and Walter Elliot were noted archaeologists/epigraphists associated with the Archaeological Survey and excavations, especially in South India.
• (b) Establishment of English Press in Colonial India — Incorrect. These names are not associated with founding the English press; that field is linked to early colonial journalists and printers.
• (c) Establishment of Churches in Princely States — Incorrect. They were not church founders or missionaries; their work was in archaeology, inscriptions and antiquarian studies.
• (d) Construction of railways in Colonial India — Incorrect. They were not railway engineers or administrators connected with railway construction.

Therefore, the correct answer is (a).