Which one of the following equations represents the downstream

Which one of the following equations represents the downstream profile of Ogee spillway with vertical upstream face {(x,y) are the co-ordinates of the point on the downstream profile with origin at the crust of the raliway and H_d is the design head

The downstream profile of the ogee creat may confirm to the following equation : x^1.85 = K₂ H_d^0.85 y₂

y	= 0.5		x		^1.85
H_d			H_x

y	= -0.5		x		^{1 /1.85}
H_d			H_d

y	= -2.0		x		^1.85
H_d			H_d

y	= -2.0		x		^{1 / 1.85}
H_d			H_d