If it is a 2×200 meters relay, in which each of the two runners run 200 meters each, the best combination is:
Choice (1) - Chandran + Easwar = 23 + 23 = 46 seconds. Choice (2) - Chandran + Dinu = 23 + 23 = 46 seconds.
Choice (3) - Dinu + Easwar = 23 + 23 = 46 seconds. All three choices give the same answer. Hence, choice (4) is correct. Note again that for each of them this will be their first 200 m.