Solution:(b) Salim Ali decided to devote his life to the preservation of Indian birds. (Correct)(a) Salim devoted his life to the preservation of Indian birds. (Main verb is missing)
(c) Salim Ali has decided to devote his life to the preservation of Indian birds. (Incorrect Tense)
(d) Salim Ali had decided to devote his life to the preservation of Indian birds. (Incorrect Tense)