Select the number that can replace the question mark (?) in the following series.
234, 197, 160, ? , 86, 49

Correct option is D

The pattern in the series:
234 - 197 = 37
197 - 160 = 37
160 - ? = 37
So, each number decreases by 37.
Thus, the missing number is: 160 - 37 = 123.
Checking the next step:
123 - 86 = 37
86 - 49 = 37
The consistent difference confirms the pattern. Therefore, the missing number is 123, and the correct answer is (d).