If the circle x2 + y2 = 4, a (- 1,0) and B (1,0) move the parabola through two points a and B, and the tangent of the circle is taken as the guide line, then the focus trajectory equation of the parabola is () A. x25+y23＝1(y≠0)B. x24+y23＝1(y≠0)C. x25+y24＝1(y≠0)D. x23+y24＝1(y≠0)

If the circle x2 + y2 = 4, a (- 1,0) and B (1,0) move the parabola through two points a and B, and the tangent of the circle is taken as the guide line, then the focus trajectory equation of the parabola is () A. x25+y23＝1(y≠0)B. x24+y23＝1(y≠0)C. x25+y24＝1(y≠0)D. x23+y24＝1(y≠0)

The sum of the distances from the focus to a and B is equal to the sum of the distances from a and B to the directrix respectively, and the sum of the distances is twice the distance from the midpoint o of a and B to the directrix, that is, 2R = 4, so the trajectory equation c of the focus is an ellipse with a and B as the focus, where a is 2 and C is 1. The trajectory equation is x24 + Y23 = 1 (Y ≠ 0)