The correct option is C 8,6
9x2−16y2+72x−32y−16=0
⇒9(x2+8x)−16(y2+2y)=16
⇒9(x2+8x+16)−16(y2+2y+1)=16+144−16
⇒9(x+4)2−16(y+1)2=144
⇒(x+4)242−(y+1)32=1
⇒a=4,b=3
Thus length of the axes of the given parabola are 2a and 2b respectively i.e 8 and 6.
Hence, option 'B' is correct