Correct option is C
Given: 18, 49, 18, 45, 18, 41, 18, (?)
Logic: Each alternate number in the series (the numbers at odd places) is 18.
Also, subtract 4 from each alternate term (the numbers at even places) to get the next alternate term.
49 - 4 = 45
45 - 4 = 41
Similarly, 41 - 4 = 37
Thus, the correct answer is (c).