Answer:
A.

Explanation:
From the image attached below statement we understand that a parabola with a horizontal axis of symmetry and whose vertex is centered at
is defined by the following expression:
(1)
Where
is the parabola factor, when
, the parabola is oriented in the +x direction, otherwise is oriented in the -x direction. Hence, we may conclude that equation of the parabola is of the form:

, where

The correct answer is A.