Explanation:

- Simplify the expression: *12 + 2.5 + (1.5 of 4) - 2.6*.

- Breakdown the steps:

- *1.5 of 4* means multiplying 1.5 by 4, which is 6.

- The expression now reads: *12 + 2.5 + 6 - 2.6*.

- Add the numbers: 12 + 2.5 = 14.5.

- Add the result to 6: 14.5 + 6 = 20.5.

- Subtract 2.6 from 20.5: 20.5 - 2.6 = 17.9.

- Option 1 is 17.9.

- Option 2 is 18.9.

- Option 3 is 18.1.

- Option 4 is 17.1.

- Correct Answer: Option 1, 17.9