This is a simple addition series with a random number, 8, interpolated as every other number.

Correct Option: D

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 addition series, 1 is added to the first number; 2 is added to the second number;

Correct Option: D

In this addition series, 1 is added to the first number; 2 is added to the second number; 3 is added to the third number; and so forth.

This is a simple subtraction series.

Correct Option: A

This is a simple subtraction series. Each number is 35 less than the previous number.

This is an alternation with repetition series

Correct Option: C

This is an alternation with repetition series in which each number repeats itself and then increases by 7.

This is a simple subtraction series.

Correct Option: B

This is a simple subtraction series. Each number is 6 less than the previous number.