Explanation:

Let’s analyze the sequence: 7, 7, 9, 27, 31, 155, ?

- The first two numbers are both 7.

- 3rd: 9 (7 + 2)

- 4th: 27 (9 × 3)

- 5th: 31 (27 + 4)

- 6th: 155 (31 × 5)

- 7th: ? (155 + 6 = 161)

If we look closely, the operations alternate:

- Add 2

- Multiply by 3

- Add 4

- Multiply by 5

- Add 6

So next should be Multiply by 7 (155 × 7 = 1085), *but* following the alternating pattern, we're currently on the “add” step. So, correct operation is Add 6.

155 + 6 = 161

Correct option: Option:2, 161