This is an alternating addition series with a random number, 4, interpolated as every third number.

Correct Option: D

This is an alternating addition series with a random number, 4, interpolated as every third number. In the main series, 1 is added, then 2 is added, then 1, then 2, and so on.

This is an alternating repetition series, in which a random number, 61, is interpolated as every third number into an otherwise simple subtraction series.

Correct Option: E

This is an alternating repetition series, in which a random number, 61, is interpolated as every third number into an otherwise simple subtraction series. Starting with the second number, 57, each number (except 61) is 7 less than the previous number.

This is an alternating addition and subtraction series. In the first pattern, 2 is added to each number to arrive at the next;

Correct Option: D

This is an alternating addition and subtraction series. In the first pattern, 2 is added to each number to arrive at the next; in the alternate pattern, 6 is subtracted from each number to arrive at the next.

In this simple addition series,

Correct Option: D

In this simple addition series, each number is 5 more than the previous number.

Two patterns alternate here, with every third number following the alternate pattern. In the main series, beginning with 4, 3 is added to each number to arrive at the next.

Correct Option: E

Two patterns alternate here, with every third number following the alternate pattern. In the main series, beginning with 4, 3 is added to each number to arrive at the next. In the alternating series, beginning with 26, 6 is subtracted from each number to arrive at the next.