Given:

Let's find the length of the major axis of the given conic section.
Apply the equation of an ellipse:

Where b is greater than a.
The length of the major axis is = 2b
We have:
![\begin{gathered} a=\sqrt[]{25}=5 \\ \\ b=\sqrt[]{49}=7 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/upjs0six4eku1cbddjc26sbarkh5k0jenx.png)
Here, b is greater than a.
Therefore, the length of the major axis is = 2b.
Where:
b = 7
Length of major axis = 2b = 2(7) = 14
Therefore, the length of the major axis is 14.
ANSWER:
D. 14