Answer:
The correct option is 4. The vertex of the parabola is (10,800).
Explanation:
If a quadratic function is defined as
![y=ax^2+bx+c](https://img.qammunity.org/2019/formulas/mathematics/high-school/df9zjslv5nlii4w2w8fyvev3848jkrh9r5.png)
then its vertex is
![(-(b)/(2a),f(-(b)/(2a)))](https://img.qammunity.org/2019/formulas/mathematics/high-school/b69zww14whhbitt808vjqv7wyjw0h65l7p.png)
The given quadratic function is
![f(x)=-2x^2+40x+600](https://img.qammunity.org/2019/formulas/mathematics/high-school/eabddd8kspgxib2nuzedul3a1n3yqeqbdy.png)
Here, a=-2, b=40 c=400.
![-(b)/(2a)=-((40)/(2(-2))=10](https://img.qammunity.org/2019/formulas/mathematics/high-school/opnsbx6avol7uuobrl8qyy479sfks1g63e.png)
Substitute x=10 in the given function.
![f(10)=-2(10)^2+40(10)+600=800](https://img.qammunity.org/2019/formulas/mathematics/high-school/ls6tggd1f0ittote589m118rarnargv0l6.png)
The vertex of the given function is (10,800). Therefore correct option is 4.