Explanation:

- Let's analyze the given series: 2, 5, 11, 23, 44, ?

- Notice the pattern in differences:

- The difference between 5 and 2 is 3.

- The difference between 11 and 5 is 6.

- The difference between 23 and 11 is 12.

- The difference between 44 and 23 is 21.

- The differences are increasing as: 3, 6, 12, 21.

- These increments suggest adding consecutive triangular numbers (3, 6, 10, 15, etc.).

- The next difference should be 33 (21 + 12).

- Therefore, add 33 to 44.

- 44 + 33 = 77.

- This means the next number in the series is 77.

- Option 4: 77 is correct.