The sum of the focal distances from any point on the ellipse $9x^2 + 16y^2 = 144$ is

**Write the ellipse in standard form:** $$\frac{x^2}{16}+\frac{y^2}{9}=1.$$ Hence the semi-major axis is $a=4$. For any point on an ellipse, the sum of distances from the two foci is $2a$. **Therefore the required sum is $$2a=8.$$ Comparing with the options, the matching choice is $8$.**