Explanation:

- Let's assume the ages of the two friends are 7x and 9x.

- In 10 years, their ages will be (7x + 10) and (9x + 10).

- The future age ratio is given as 19:23.

- Set up the equation: (7x + 10)/(9x + 10) = 19/23.

- Solving the equation, 23(7x + 10) = 19(9x + 10).

- This simplifies to 161x + 230 = 171x + 190.

- Rearranging gives: 10x = 40, so x = 4.

- Current ages are 7x = 28 and 9x = 36.

- Average age in 7 years is (28+7+36+7)/2 = 39 years.

- The correct option is Option 4: 39 years.