Answer:
D. Circle; (x²) + (y²)-4=0
Explanation
Simplify the equation by dividing both sides by 2
2x² + 2y² =8
x² + y² =4
this gives a circle form where we can apply (x-h) ² +(y-k)² =r² to find center and radius of the circle.
Thus r=2, h=0, k=0
Center of circle is at (h, k), (0,0)
Radius of circle is 2