Correct option is B
In the given series prime number are added like 5, 7, 11… etc. patter is followed-
18, 23, ?, 41, 54, 71
18 → 18 + 5 = 23
23 → 23 + 7 = 30
30 → 31 + 11 = 41
41→ 41 + 13 = 54
54 → 54 + 17 = 71
Therefore, the correct option is (b).