Solution:(c) I said to him, "If you go around the park you will see some rare flowers." (Correct)(a) I said to him, "If you went around the park you would see some rare flowers." (Change of reported speech to simple past is incorrect)
(b) I said to him, "If you go around the park you would saw some rare flowers."("would and saw" are incorrect)
(d) I said to him, "If he went around the park he will see some rare flowers." (Incorrect change of reported speech to simple past and also usage of "he")