Atunnel is being built through a mountain. the tunnel is a semi-ellipse. the tunnel is 49 feet high and 196 feet wide. what is the equation for the ellipse?

What we know:
Shape is semi-ellipse
Ellipse equation in this direction: x²/b²+ y²/a²=1
height is 49 ft
width is 196 ft

What we need to find:
Equation of the ellipse that represents the tunnel with height 49 ft and width of 196 ft.

x²/a²+ y²/b²=1
x²/98²+ y²/49²=1

B. x²/98²+ y²/49²=1

Idk idk idk idk idk idk