In the meaning of the question, point H is: the straight line at any two points (p, a) on the ellipse X 2/4+Y 2 =1and the intersection point B of the straight line l(x=4).

Point A or P is the midpoint of a line segment (PB or AB).

According to symmetry, as long as p is considered as the midpoint, that is, x [p] >; =0

Let l be a symmetrical straight line l' about point p,

If l' intersects the ellipse, we can find the point A, so that PA=PB.

If l' does not intersect the ellipse, such a point A does not exist, that is, the point P is not "h".

x[A]=2x[P]-x[B]=2x[P]-4

Obviously,

When x [p]

When x [p] >; When = 1, if there is intersection, then P is "H point".

So the answer is d.