Explanation:

- The first 13 odd numbers are 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, and 25.

- To find the average, add all the numbers together and divide by 13:

$$(1+3+5+7+9+11+13+15+17+19+21+23+25)÷13.$$

- The sum is 169.

- Dividing 169 by 13 gives us 13.

- Option 1: 14 – Incorrect, the average is not 14.

- Option 2: 13.5 – Incorrect, doesn't match the calculated average.

- Option 3: 12 – Incorrect, lower than the actual average.

- Option 4: 13 – Correct answer.