The correct option is B (−b2a,−D4a)
We know that, the coordinates of the vertex of parabola of the form (x−h)2=4a(y−k) are (h,k)So, y=ax2+bx+c can be written as:ya=x2+ba⋅x+ca⇒ya=x2+2⋅b2a⋅x+(b2a)2−(b2a)2+ca⇒ya=(x+b2a)2−b24a2+ca⇒(x+b2a)2=ya+b24a2−ca⇒(x+b2a)2=ya+√D4a2⇒(x+b2a)2=1a(y+√D4a)Hence, the coordinates of the vertex of the given parabola is (−b2a,−√D4a)