Jon P. answered 04/09/15
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x2 + 4x +8y - 20 = 0
You can see that there is a square term for x, but not for y. A curve that has a square term for one variable but not the other is a parabola.
That means that b and c cannot be correct.
Also, parabolas do not have asymptotes, so d can't be correct either.
The only answer left is a.