Correct option is D
The series is:111, 122, 133, ?, 155, 166
Let's start with the first term and keep adding 11 to each:
111 + 11 = 122
122 + 11 = 133
133 + 11 = 144 (This is the missing number)
144 + 11 = 155
155 + 11 = 166
The missing number is 144.
Correct answer is (d) 144