This is a simple addition series with a random number, 8, interpolated as every other number.
In the series, 6 is added to each number except 8, to arrive at the next number.
In this Series 8 is common number.
Now add 6 with 22 or 28.
22 + 6 = 28
28 + 6 = 34.
So the answer is d = 34.