Which is the equation of a hyperbola with directrices at y = ±2 and foci at (0, 4) and (0, −4)?
 x squared over 8 minus y squared over 16 equals 1
 y squared over 16 minus x squared over 8 equals 1
 x squared over 8 minus y squared over 8 equals 1
 y squared over 8 minus x squared over 8 equals 1