we are given
[tex] y= -x^2 + 6x + 7 [/tex]
we can use vertex form parabola formula
[tex] y= a(x-h)^2+k [/tex]
so, we can complete x square
[tex] y= -(x^2 - 6x - 7) [/tex]
[tex] y= -(x^2 - 6x - 7+3^2-3^2) [/tex]
[tex] y= -(x^2 - 6x +3^2-16) [/tex]
[tex] y= -(x-3)^2+16 [/tex]
so, option-A........................Answer
